diff --git a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/.publicApi/PublicAPI.Shipped.txt b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/.publicApi/PublicAPI.Shipped.txt
index e69de29bb2..7dc5c58110 100644
--- a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/.publicApi/PublicAPI.Shipped.txt
+++ b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/.publicApi/PublicAPI.Shipped.txt
@@ -0,0 +1 @@
+#nullable enable
diff --git a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/.publicApi/PublicAPI.Unshipped.txt b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/.publicApi/PublicAPI.Unshipped.txt
index 95461d9b80..a3c6cc40bf 100644
--- a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/.publicApi/PublicAPI.Unshipped.txt
+++ b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/.publicApi/PublicAPI.Unshipped.txt
@@ -1,6 +1,6 @@
 OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions
 OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions.ElasticsearchClientInstrumentationOptions() -> void
-OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions.Enrich.get -> System.Action<System.Diagnostics.Activity, string, object>
+OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions.Enrich.get -> System.Action<System.Diagnostics.Activity!, string!, object?>?
 OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions.Enrich.set -> void
 OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions.MaxDbStatementLength.get -> int
 OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions.MaxDbStatementLength.set -> void
@@ -11,6 +11,6 @@ OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumenta
 OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions.SuppressDownstreamInstrumentation.get -> bool
 OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions.SuppressDownstreamInstrumentation.set -> void
 OpenTelemetry.Trace.TracerProviderBuilderExtensions
-static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddElasticsearchClientInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder builder, System.Action<OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions> configure) -> OpenTelemetry.Trace.TracerProviderBuilder
-static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddElasticsearchClientInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder builder) -> OpenTelemetry.Trace.TracerProviderBuilder
-static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddElasticsearchClientInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder builder, string name, System.Action<OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions> configure) -> OpenTelemetry.Trace.TracerProviderBuilder
\ No newline at end of file
+static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddElasticsearchClientInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder! builder, System.Action<OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions!>? configure) -> OpenTelemetry.Trace.TracerProviderBuilder!
+static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddElasticsearchClientInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder! builder) -> OpenTelemetry.Trace.TracerProviderBuilder!
+static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddElasticsearchClientInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder! builder, string? name, System.Action<OpenTelemetry.Instrumentation.ElasticsearchClient.ElasticsearchClientInstrumentationOptions!>? configure) -> OpenTelemetry.Trace.TracerProviderBuilder!
diff --git a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/ElasticsearchClientInstrumentationOptions.cs b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/ElasticsearchClientInstrumentationOptions.cs
index dcb91ef5c1..3c7e647ef4 100644
--- a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/ElasticsearchClientInstrumentationOptions.cs
+++ b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/ElasticsearchClientInstrumentationOptions.cs
@@ -41,5 +41,5 @@ public class ElasticsearchClientInstrumentationOptions
     /// <para>object: the raw object from which additional information can be extracted to enrich the activity.
     /// The type of this object depends on the event, which is given by the above parameter.</para>
     /// </remarks>
-    public Action<Activity, string, object> Enrich { get; set; }
+    public Action<Activity, string, object?>? Enrich { get; set; }
 }
diff --git a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/Implementation/ElasticsearchRequestPipelineDiagnosticListener.cs b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/Implementation/ElasticsearchRequestPipelineDiagnosticListener.cs
index af907e627d..315c7a4e44 100644
--- a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/Implementation/ElasticsearchRequestPipelineDiagnosticListener.cs
+++ b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/Implementation/ElasticsearchRequestPipelineDiagnosticListener.cs
@@ -28,17 +28,17 @@ internal class ElasticsearchRequestPipelineDiagnosticListener : ListenerHandler
     internal static readonly string ActivitySourceName = AssemblyName.Name;
     internal static readonly ActivitySource ActivitySource = new(ActivitySourceName, Assembly.GetPackageVersion());
 
-    private static readonly Regex ParseRequest = new Regex(@"\n# Request:\r?\n(\{.*)\n# Response", RegexOptions.Compiled | RegexOptions.Singleline);
-    private static readonly ConcurrentDictionary<object, string> MethodNameCache = new ConcurrentDictionary<object, string>();
+    private static readonly Regex ParseRequest = new(@"\n# Request:\r?\n(\{.*)\n# Response", RegexOptions.Compiled | RegexOptions.Singleline);
+    private static readonly ConcurrentDictionary<object, string> MethodNameCache = new();
 
     private readonly ElasticsearchClientInstrumentationOptions options;
-    private readonly MultiTypePropertyFetcher<Uri> uriFetcher = new MultiTypePropertyFetcher<Uri>("Uri");
-    private readonly MultiTypePropertyFetcher<object> methodFetcher = new MultiTypePropertyFetcher<object>("Method");
-    private readonly MultiTypePropertyFetcher<string> debugInformationFetcher = new MultiTypePropertyFetcher<string>("DebugInformation");
-    private readonly MultiTypePropertyFetcher<int?> httpStatusFetcher = new MultiTypePropertyFetcher<int?>("HttpStatusCode");
-    private readonly MultiTypePropertyFetcher<Exception> originalExceptionFetcher = new MultiTypePropertyFetcher<Exception>("OriginalException");
-    private readonly MultiTypePropertyFetcher<object> failureReasonFetcher = new MultiTypePropertyFetcher<object>("FailureReason");
-    private readonly MultiTypePropertyFetcher<byte[]> responseBodyFetcher = new MultiTypePropertyFetcher<byte[]>("ResponseBodyInBytes");
+    private readonly MultiTypePropertyFetcher<Uri> uriFetcher = new("Uri");
+    private readonly MultiTypePropertyFetcher<object> methodFetcher = new("Method");
+    private readonly MultiTypePropertyFetcher<string> debugInformationFetcher = new("DebugInformation");
+    private readonly MultiTypePropertyFetcher<int?> httpStatusFetcher = new("HttpStatusCode");
+    private readonly MultiTypePropertyFetcher<Exception> originalExceptionFetcher = new("OriginalException");
+    private readonly MultiTypePropertyFetcher<object> failureReasonFetcher = new("FailureReason");
+    private readonly MultiTypePropertyFetcher<byte[]> responseBodyFetcher = new("ResponseBodyInBytes");
 
     public ElasticsearchRequestPipelineDiagnosticListener(ElasticsearchClientInstrumentationOptions options)
         : base("Elasticsearch.Net.RequestPipeline")
@@ -46,7 +46,7 @@ public ElasticsearchRequestPipelineDiagnosticListener(ElasticsearchClientInstrum
         this.options = options;
     }
 
-    public override void OnEventWritten(string name, object payload)
+    public override void OnEventWritten(string name, object? payload)
     {
         var activity = Activity.Current;
         Guard.ThrowIfNull(activity);
@@ -61,7 +61,7 @@ public override void OnEventWritten(string name, object payload)
         }
     }
 
-    private static string GetDisplayName(Activity activity, object method, string elasticType = null)
+    private static string GetDisplayName(Activity activity, object? method, string? elasticType = null)
     {
         switch (activity.OperationName)
         {
@@ -83,7 +83,7 @@ private static string GetDisplayName(Activity activity, object method, string el
         }
     }
 
-    private static string GetElasticIndex(Uri uri)
+    private static string? GetElasticIndex(Uri uri)
     {
         // first segment is always /
         if (uri.Segments.Length < 2)
@@ -91,7 +91,7 @@ private static string GetElasticIndex(Uri uri)
             return null;
         }
 
-        // operations starting with _ are not indices (_cat, _search, etc)
+        // operations starting with _ are not indices (_cat, _search, etc.)
         if (uri.Segments[1].StartsWith("_", StringComparison.Ordinal))
         {
             return null;
@@ -123,7 +123,7 @@ private string ParseAndFormatRequest(string debugInformation)
         var request = ParseRequest.Match(debugInformation);
         if (request.Success)
         {
-            string body = request.Groups[1]?.Value?.Trim();
+            string? body = request.Groups[1]?.Value?.Trim();
             if (body == null)
             {
                 return debugInformation;
@@ -150,7 +150,7 @@ private string ParseAndFormatRequest(string debugInformation)
         return debugInformation;
     }
 
-    private void OnStartActivity(Activity activity, object payload)
+    private void OnStartActivity(Activity activity, object? payload)
     {
         // By this time, samplers have already run and
         // activity.IsAllDataRequested populated accordingly.
@@ -226,7 +226,7 @@ private void OnStartActivity(Activity activity, object payload)
         }
     }
 
-    private void OnStopActivity(Activity activity, object payload)
+    private void OnStopActivity(Activity activity, object? payload)
     {
         if (activity.IsAllDataRequested)
         {
diff --git a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/OpenTelemetry.Instrumentation.ElasticsearchClient.csproj b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/OpenTelemetry.Instrumentation.ElasticsearchClient.csproj
index 30383291e8..8bd24ba026 100644
--- a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/OpenTelemetry.Instrumentation.ElasticsearchClient.csproj
+++ b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/OpenTelemetry.Instrumentation.ElasticsearchClient.csproj
@@ -6,7 +6,6 @@
     <Description>Elasticsearch instrumentation for OpenTelemetry .NET</Description>
     <PackageTags>$(PackageTags);distributed-tracing</PackageTags>
     <MinVerTagPrefix>Instrumentation.ElasticsearchClient-</MinVerTagPrefix>
-    <Nullable>disable</Nullable>
   </PropertyGroup>
 
   <!--Do not run Package Baseline Validation as this package has never released a stable version.
diff --git a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/TracerProviderBuilderExtensions.cs b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/TracerProviderBuilderExtensions.cs
index c809d5aa7c..4ecb84181b 100644
--- a/src/OpenTelemetry.Instrumentation.ElasticsearchClient/TracerProviderBuilderExtensions.cs
+++ b/src/OpenTelemetry.Instrumentation.ElasticsearchClient/TracerProviderBuilderExtensions.cs
@@ -32,7 +32,7 @@ public static TracerProviderBuilder AddElasticsearchClientInstrumentation(
     /// <returns>The instance of <see cref="TracerProviderBuilder"/> to chain the calls.</returns>
     public static TracerProviderBuilder AddElasticsearchClientInstrumentation(
         this TracerProviderBuilder builder,
-        Action<ElasticsearchClientInstrumentationOptions> configure) =>
+        Action<ElasticsearchClientInstrumentationOptions>? configure) =>
         AddElasticsearchClientInstrumentation(builder, name: null, configure);
 
     /// <summary>
@@ -44,8 +44,8 @@ public static TracerProviderBuilder AddElasticsearchClientInstrumentation(
     /// <returns>The instance of <see cref="TracerProviderBuilder"/> to chain the calls.</returns>
     public static TracerProviderBuilder AddElasticsearchClientInstrumentation(
         this TracerProviderBuilder builder,
-        string name,
-        Action<ElasticsearchClientInstrumentationOptions> configure)
+        string? name,
+        Action<ElasticsearchClientInstrumentationOptions>? configure)
     {
         Guard.ThrowIfNull(builder);
 
diff --git a/src/Shared/ActivityInstrumentationHelper.cs b/src/Shared/ActivityInstrumentationHelper.cs
index 31418f1642..427532047d 100644
--- a/src/Shared/ActivityInstrumentationHelper.cs
+++ b/src/Shared/ActivityInstrumentationHelper.cs
@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-#nullable disable
+#nullable enable
 
 #pragma warning disable IDE0005 // Using directive is unnecessary.
 using System;
@@ -17,13 +17,13 @@ internal static class ActivityInstrumentationHelper
 
     private static Action<Activity, ActivitySource> CreateActivitySourceSetter()
     {
-        return (Action<Activity, ActivitySource>)typeof(Activity).GetProperty("Source")
-            .SetMethod.CreateDelegate(typeof(Action<Activity, ActivitySource>));
+        return (Action<Activity, ActivitySource>)typeof(Activity).GetProperty("Source")!
+            .SetMethod!.CreateDelegate(typeof(Action<Activity, ActivitySource>));
     }
 
     private static Action<Activity, ActivityKind> CreateActivityKindSetter()
     {
-        return (Action<Activity, ActivityKind>)typeof(Activity).GetProperty("Kind")
-            .SetMethod.CreateDelegate(typeof(Action<Activity, ActivityKind>));
+        return (Action<Activity, ActivityKind>)typeof(Activity).GetProperty("Kind")!
+            .SetMethod!.CreateDelegate(typeof(Action<Activity, ActivityKind>));
     }
 }
diff --git a/src/Shared/ListenerHandler.cs b/src/Shared/ListenerHandler.cs
index 299146eb74..a7c6f9049d 100644
--- a/src/Shared/ListenerHandler.cs
+++ b/src/Shared/ListenerHandler.cs
@@ -16,7 +16,7 @@ internal abstract class ListenerHandler
     /// Initializes a new instance of the <see cref="ListenerHandler"/> class.
     /// </summary>
     /// <param name="sourceName">The name of the <see cref="ListenerHandler"/>.</param>
-    public ListenerHandler(string sourceName)
+    protected ListenerHandler(string sourceName)
     {
         this.SourceName = sourceName;
     }
diff --git a/src/Shared/MultiTypePropertyFetcher.cs b/src/Shared/MultiTypePropertyFetcher.cs
index 696a7bd7ad..c925d2e736 100644
--- a/src/Shared/MultiTypePropertyFetcher.cs
+++ b/src/Shared/MultiTypePropertyFetcher.cs
@@ -1,14 +1,12 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-#nullable disable
+#nullable enable
 
-#pragma warning disable IDE0005 // Using directive is unnecessary.
 using System;
 using System.Collections.Concurrent;
 using System.Linq;
 using System.Reflection;
-#pragma warning restore IDE0005 // Using directive is unnecessary.
 
 namespace OpenTelemetry.Instrumentation;
 
@@ -16,12 +14,10 @@ namespace OpenTelemetry.Instrumentation;
 /// PropertyFetcher fetches a property from an object.
 /// </summary>
 /// <typeparam name="T">The type of the property being fetched.</typeparam>
-#pragma warning disable CA1812
 internal sealed class MultiTypePropertyFetcher<T>
-#pragma warning restore CA1812
 {
     private readonly string propertyName;
-    private readonly ConcurrentDictionary<Type, PropertyFetch> innerFetcher = new ConcurrentDictionary<Type, PropertyFetch>();
+    private readonly ConcurrentDictionary<Type, PropertyFetch> innerFetcher = new();
 
     /// <summary>
     /// Initializes a new instance of the <see cref="MultiTypePropertyFetcher{T}"/> class.
@@ -37,7 +33,7 @@ public MultiTypePropertyFetcher(string propertyName)
     /// </summary>
     /// <param name="obj">Object to be fetched.</param>
     /// <returns>Property fetched.</returns>
-    public T Fetch(object obj)
+    public T? Fetch(object? obj)
     {
         if (obj == null)
         {
@@ -45,8 +41,7 @@ public T Fetch(object obj)
         }
 
         var type = obj.GetType().GetTypeInfo();
-        PropertyFetch fetcher = null;
-        if (!this.innerFetcher.TryGetValue(type, out fetcher))
+        if (!this.innerFetcher.TryGetValue(type, out var fetcher))
         {
             var property = type.DeclaredProperties.FirstOrDefault(p => string.Equals(p.Name, this.propertyName, StringComparison.OrdinalIgnoreCase));
             if (property == null)
@@ -88,7 +83,7 @@ public static PropertyFetch FetcherForProperty(PropertyInfo propertyInfo)
             return (PropertyFetch)Activator.CreateInstance(instantiatedTypedPropertyFetcher, propertyInfo);
         }
 
-        public virtual T Fetch(object obj)
+        public virtual T? Fetch(object obj)
         {
             return default;
         }
@@ -105,7 +100,7 @@ public TypedPropertyFetch(PropertyInfo property)
                 this.propertyFetch = (Func<TDeclaredObject, TDeclaredProperty>)property.GetMethod.CreateDelegate(typeof(Func<TDeclaredObject, TDeclaredProperty>));
             }
 
-            public override T Fetch(object obj)
+            public override T? Fetch(object obj)
             {
                 if (obj is TDeclaredObject o)
                 {
diff --git a/src/Shared/PropertyFetcher.AOT.cs b/src/Shared/PropertyFetcher.AOT.cs
index a4f522263d..d15193a40a 100644
--- a/src/Shared/PropertyFetcher.AOT.cs
+++ b/src/Shared/PropertyFetcher.AOT.cs
@@ -1,8 +1,6 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-#nullable disable
-
 // NOTE: This version of PropertyFetcher is AOT-compatible.
 // Usages of the non-AOT-compatible version can be moved over to this one when they need to support AOT/trimming.
 // Copied from https://github.com/open-telemetry/opentelemetry-dotnet/blob/86a6ba0b7f7ed1f5e84e5a6610e640989cd3ae9f/src/Shared/DiagnosticSourceInstrumentation/PropertyFetcher.cs#L30
diff --git a/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Areas/AnotherArea/Controllers/AnotherAreaController.cs b/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Areas/AnotherArea/Controllers/AnotherAreaController.cs
index 7754255edf..626c69da6f 100644
--- a/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Areas/AnotherArea/Controllers/AnotherAreaController.cs
+++ b/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Areas/AnotherArea/Controllers/AnotherAreaController.cs
@@ -1,8 +1,6 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-#nullable disable
-
 using Microsoft.AspNetCore.Mvc;
 
 namespace RouteTests.Controllers;
diff --git a/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Areas/MyArea/Controllers/ControllerForMyAreaController.cs b/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Areas/MyArea/Controllers/ControllerForMyAreaController.cs
index 762f4a95e8..fabece0296 100644
--- a/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Areas/MyArea/Controllers/ControllerForMyAreaController.cs
+++ b/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Areas/MyArea/Controllers/ControllerForMyAreaController.cs
@@ -1,8 +1,6 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-#nullable disable
-
 using Microsoft.AspNetCore.Mvc;
 
 namespace RouteTests.Controllers;
diff --git a/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Controllers/AttributeRouteController.cs b/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Controllers/AttributeRouteController.cs
index b1e5783b0a..93e4174166 100644
--- a/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Controllers/AttributeRouteController.cs
+++ b/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Controllers/AttributeRouteController.cs
@@ -1,8 +1,6 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-#nullable disable
-
 using Microsoft.AspNetCore.Mvc;
 
 namespace RouteTests.Controllers;
diff --git a/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Controllers/ConventionalRouteController.cs b/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Controllers/ConventionalRouteController.cs
index 977ee36a13..ac6bc3be0f 100644
--- a/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Controllers/ConventionalRouteController.cs
+++ b/test/OpenTelemetry.Instrumentation.AspNetCore.Tests/RouteTests/TestApplication/Controllers/ConventionalRouteController.cs
@@ -1,8 +1,6 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-#nullable disable
-
 using Microsoft.AspNetCore.Mvc;
 
 namespace RouteTests.Controllers;
diff --git a/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/Customer.cs b/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/Customer.cs
index 369171f5f4..2ace4b977c 100644
--- a/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/Customer.cs
+++ b/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/Customer.cs
@@ -5,7 +5,7 @@ namespace OpenTelemetry.Instrumentation.ElasticsearchClient.Tests;
 
 public class Customer
 {
-    public string Id { get; set; }
+    public string? Id { get; set; }
 
-    public string Name { get; set; }
+    public string? Name { get; set; }
 }
diff --git a/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/DependencyInjectionConfigTests.cs b/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/DependencyInjectionConfigTests.cs
index 6a0775b7f1..736945d141 100644
--- a/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/DependencyInjectionConfigTests.cs
+++ b/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/DependencyInjectionConfigTests.cs
@@ -16,7 +16,7 @@ public class DependencyInjectionConfigTests
     [Theory]
     [InlineData(null)]
     [InlineData("CustomName")]
-    public async Task TestTracingOptionsDiConfig(string name)
+    public async Task TestTracingOptionsDiConfig(string? name)
     {
         bool optionsPickedFromDi = false;
 
diff --git a/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/ElasticsearchClientTests.cs b/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/ElasticsearchClientTests.cs
index f9db99cbcb..41dd366fa3 100644
--- a/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/ElasticsearchClientTests.cs
+++ b/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/ElasticsearchClientTests.cs
@@ -67,7 +67,8 @@ public async Task CanCaptureGetById()
 
         Assert.Equal("elasticsearch", searchActivity.GetTagValue(SemanticConventions.AttributeDbSystem));
         Assert.Equal("customer", searchActivity.GetTagValue(SemanticConventions.AttributeDbName));
-        var debugInfo = (string)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        var debugInfo = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        Assert.NotNull(debugInfo);
         Assert.NotEmpty(debugInfo);
         Assert.Contains("Successful (200) low level call", debugInfo);
 
@@ -119,7 +120,8 @@ public async Task CanCaptureGetByIdNotFound()
 
         Assert.Equal("elasticsearch", searchActivity.GetTagValue(SemanticConventions.AttributeDbSystem));
         Assert.Equal("customer", searchActivity.GetTagValue(SemanticConventions.AttributeDbName));
-        var debugInfo = (string)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        var debugInfo = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        Assert.NotNull(debugInfo);
         Assert.NotEmpty(debugInfo);
         Assert.Contains("Successful (404) low level call", debugInfo);
 
@@ -170,7 +172,8 @@ public async Task CanCaptureSearchCall()
 
         Assert.Equal("elasticsearch", searchActivity.GetTagValue(SemanticConventions.AttributeDbSystem));
         Assert.Equal("customer", searchActivity.GetTagValue(SemanticConventions.AttributeDbName));
-        var debugInfo = (string)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        var debugInfo = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        Assert.NotNull(debugInfo);
         Assert.NotEmpty(debugInfo);
         Assert.Contains("Successful (200) low level call", debugInfo);
 
@@ -401,7 +404,8 @@ public async Task CanCaptureSearchCallWithDebugMode()
 
         Assert.Equal("elasticsearch", searchActivity.GetTagValue(SemanticConventions.AttributeDbSystem));
         Assert.Equal("customer", searchActivity.GetTagValue(SemanticConventions.AttributeDbName));
-        var debugInfo = (string)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        var debugInfo = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        Assert.NotNull(debugInfo);
         Assert.NotEmpty(debugInfo);
         Assert.Contains("Successful (200) low level call", debugInfo);
 
@@ -451,7 +455,8 @@ public async Task CanCaptureSearchCallWithParseAndFormatRequestOption()
 
         Assert.Equal("elasticsearch", searchActivity.GetTagValue(SemanticConventions.AttributeDbSystem));
         Assert.Equal("customer", searchActivity.GetTagValue(SemanticConventions.AttributeDbName));
-        var debugInfo = (string)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        var debugInfo = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        Assert.NotNull(debugInfo);
         Assert.NotEmpty(debugInfo);
         Assert.Equal(
             @"{
@@ -518,7 +523,8 @@ public async Task CanCaptureSearchCallWithoutDebugMode()
 
         Assert.Equal("elasticsearch", searchActivity.GetTagValue(SemanticConventions.AttributeDbSystem));
         Assert.Equal("customer", searchActivity.GetTagValue(SemanticConventions.AttributeDbName));
-        var debugInfo = (string)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        var debugInfo = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        Assert.NotNull(debugInfo);
         Assert.NotEmpty(debugInfo);
         Assert.DoesNotContain("123", debugInfo);
 
@@ -569,7 +575,8 @@ public async Task CanCaptureMultipleIndiceSearchCall()
 
         Assert.Equal("elasticsearch", searchActivity.GetTagValue(SemanticConventions.AttributeDbSystem));
         Assert.Null(searchActivity.GetTagValue(SemanticConventions.AttributeDbName));
-        var debugInfo = (string)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        var debugInfo = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        Assert.NotNull(debugInfo);
         Assert.NotEmpty(debugInfo);
         Assert.Contains("Successful (200) low level call", debugInfo);
 
@@ -621,7 +628,8 @@ public async Task CanCaptureElasticsearchClientException()
 
         Assert.Equal("elasticsearch", searchActivity.GetTagValue(SemanticConventions.AttributeDbSystem));
         Assert.Equal("customer", searchActivity.GetTagValue(SemanticConventions.AttributeDbName));
-        var debugInfo = (string)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        var debugInfo = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        Assert.NotNull(debugInfo);
         Assert.NotEmpty(debugInfo);
         Assert.Contains("Unsuccessful (500) low level call", debugInfo);
 
@@ -673,7 +681,8 @@ public async Task CanCaptureCatRequest()
 
         Assert.Equal("elasticsearch", searchActivity.GetTagValue(SemanticConventions.AttributeDbSystem));
         Assert.Null(searchActivity.GetTagValue(SemanticConventions.AttributeDbName));
-        var debugInfo = (string)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        var debugInfo = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeDbStatement);
+        Assert.NotNull(debugInfo);
         Assert.NotEmpty(debugInfo);
         Assert.Contains("Successful (200) low level call", debugInfo);
 
@@ -846,7 +855,7 @@ public async Task ShouldRemoveSensitiveInformation()
         Assert.Single(exportedItems);
         var searchActivity = exportedItems[0];
 
-        string dbUrl = (string)searchActivity.GetTagValue(SemanticConventions.AttributeUrlFull);
+        string? dbUrl = (string?)searchActivity.GetTagValue(SemanticConventions.AttributeUrlFull);
 
         Assert.DoesNotContain("sensitive", dbUrl);
         Assert.Contains("REDACTED:REDACTED", dbUrl);
diff --git a/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests.csproj b/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests.csproj
index e51a2e7b55..dee17e80d3 100644
--- a/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests.csproj
+++ b/test/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests/OpenTelemetry.Instrumentation.ElasticsearchClient.Tests.csproj
@@ -4,7 +4,6 @@
     <!-- OmniSharp/VS Code requires TargetFrameworks to be in descending order for IntelliSense and analysis. -->
     <TargetFrameworks>$(SupportedNetTargets)</TargetFrameworks>
     <TargetFrameworks Condition="$(OS) == 'Windows_NT'">$(TargetFrameworks);$(NetFrameworkMinimumSupportedVersion)</TargetFrameworks>
-    <Nullable>disable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>