diff --git a/CHANGELOG.md b/CHANGELOG.md
index df552003c7..e30c56d2ae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,7 @@
 - Fixed an issue with the way Sentry detects build settings. This was causing Sentry to produce code that could fail at runtime in AOT compiled applications. ([#4333](https://github.com/getsentry/sentry-dotnet/pull/4333))
 - Native AOT: link to static `lzma` on Linux/MUSL ([#4326](https://github.com/getsentry/sentry-dotnet/pull/4326))
 - AppDomain.CurrentDomain.ProcessExit hook is now removed on shutdown ([#4323](https://github.com/getsentry/sentry-dotnet/pull/4323))
+- Include `Data` set via `ITransactionTracer` in `SentryTransaction`([#4148](https://github.com/getsentry/sentry-dotnet/pull/4148))
 
 ### Dependencies
 
diff --git a/src/Sentry/TransactionTracer.cs b/src/Sentry/TransactionTracer.cs
index 5966a224da..6d8accc745 100644
--- a/src/Sentry/TransactionTracer.cs
+++ b/src/Sentry/TransactionTracer.cs
@@ -151,15 +151,12 @@ public IReadOnlyList<string> Fingerprint
     /// <inheritdoc />
     public IReadOnlyCollection<Breadcrumb> Breadcrumbs => _breadcrumbs;
 
-    private readonly ConcurrentDictionary<string, object?> _data = new();
-
     /// <inheritdoc />
     [Obsolete("Use Data")]
-    public IReadOnlyDictionary<string, object?> Extra => _data;
+    public IReadOnlyDictionary<string, object?> Extra => _contexts.Trace.Data;
 
     /// <inheritdoc />
-    public IReadOnlyDictionary<string, object?> Data => _data;
-
+    public IReadOnlyDictionary<string, object?> Data => _contexts.Trace.Data;
 
     private readonly ConcurrentDictionary<string, string> _tags = new();
 
@@ -270,10 +267,10 @@ internal TransactionTracer(IHub hub, ITransactionContext context, TimeSpan? idle
 
     /// <inheritdoc />
     [Obsolete("Use SetData")]
-    public void SetExtra(string key, object? value) => _data[key] = value;
+    public void SetExtra(string key, object? value) => _contexts.Trace.SetData(key, value);
 
     /// <inheritdoc />
-    public void SetData(string key, object? value) => _data[key] = value;
+    public void SetData(string key, object? value) => _contexts.Trace.SetData(key, value);
 
     /// <inheritdoc />
     public void SetTag(string key, string value) => _tags[key] = value;
diff --git a/test/Sentry.AspNetCore.Tests/WebIntegrationTests.Versioning.DotNet8_0.verified.txt b/test/Sentry.AspNetCore.Tests/WebIntegrationTests.Versioning.DotNet8_0.verified.txt
index 019cc1fb2d..fcb2b33a90 100644
--- a/test/Sentry.AspNetCore.Tests/WebIntegrationTests.Versioning.DotNet8_0.verified.txt
+++ b/test/Sentry.AspNetCore.Tests/WebIntegrationTests.Versioning.DotNet8_0.verified.txt
@@ -22,7 +22,11 @@
             Origin: auto.http.aspnetcore,
             Description: ,
             Status: Ok,
-            IsSampled: true
+            IsSampled: true,
+            Data: {
+              http.request.method: GET,
+              http.response.status_code: 200
+            }
           }
         },
         User: {
@@ -80,7 +84,11 @@
           route.controller: Version,
           route.version: 1.1
         },
-        IsFinished: true
+        IsFinished: true,
+        Data: {
+          http.request.method: GET,
+          http.response.status_code: 200
+        }
       }
     }
   ]
diff --git a/test/Sentry.AspNetCore.Tests/WebIntegrationTests.Versioning.DotNet9_0.verified.txt b/test/Sentry.AspNetCore.Tests/WebIntegrationTests.Versioning.DotNet9_0.verified.txt
index 019cc1fb2d..fcb2b33a90 100644
--- a/test/Sentry.AspNetCore.Tests/WebIntegrationTests.Versioning.DotNet9_0.verified.txt
+++ b/test/Sentry.AspNetCore.Tests/WebIntegrationTests.Versioning.DotNet9_0.verified.txt
@@ -22,7 +22,11 @@
             Origin: auto.http.aspnetcore,
             Description: ,
             Status: Ok,
-            IsSampled: true
+            IsSampled: true,
+            Data: {
+              http.request.method: GET,
+              http.response.status_code: 200
+            }
           }
         },
         User: {
@@ -80,7 +84,11 @@
           route.controller: Version,
           route.version: 1.1
         },
-        IsFinished: true
+        IsFinished: true,
+        Data: {
+          http.request.method: GET,
+          http.response.status_code: 200
+        }
       }
     }
   ]
diff --git a/test/Sentry.Tests/Protocol/Context/TraceTests.cs b/test/Sentry.Tests/Protocol/Context/TraceTests.cs
index 27372d0d9a..4748688ca1 100644
--- a/test/Sentry.Tests/Protocol/Context/TraceTests.cs
+++ b/test/Sentry.Tests/Protocol/Context/TraceTests.cs
@@ -38,6 +38,7 @@ public void SerializeObject_AllPropertiesSetToNonDefault_SerializesValidObject()
             SpanId = SpanId.Parse("2000000000000000"),
             TraceId = SentryId.Parse("75302ac48a024bde9a3b3734a82e36c8")
         };
+        trace.SetData("route", "home");
 
         // Act
         var actual = trace.ToJsonString(_testOutputLogger, indented: true);
@@ -52,7 +53,10 @@ public void SerializeObject_AllPropertiesSetToNonDefault_SerializesValidObject()
               "trace_id": "75302ac48a024bde9a3b3734a82e36c8",
               "op": "op123",
               "origin": "auto.abc.def.ghi",
-              "status": "aborted"
+              "status": "aborted",
+              "data": {
+                "route": "home"
+              }
             }
             """,
             actual);
@@ -72,6 +76,7 @@ public void Clone_CopyValues()
             SpanId = SpanId.Parse("2000000000000000"),
             TraceId = SentryId.Parse("75302ac48a024bde9a3b3734a82e36c8")
         };
+        trace.SetData("previous_route", "home");
 
         // Act
         var clone = trace.Clone();
@@ -84,6 +89,7 @@ public void Clone_CopyValues()
         Assert.Equal(trace.ParentSpanId, clone.ParentSpanId);
         Assert.Equal(trace.SpanId, clone.SpanId);
         Assert.Equal(trace.TraceId, clone.TraceId);
+        Assert.Equal(trace.Data, clone.Data);
     }
 
     [Fact]
diff --git a/test/Sentry.Tests/Protocol/SentryTransactionTests.cs b/test/Sentry.Tests/Protocol/SentryTransactionTests.cs
index eb1eaf1bbf..604e1cdda7 100644
--- a/test/Sentry.Tests/Protocol/SentryTransactionTests.cs
+++ b/test/Sentry.Tests/Protocol/SentryTransactionTests.cs
@@ -258,7 +258,7 @@ public void SerializeObject_AllPropertiesSetToNonDefault_SerializesValidObject()
 
         // Act
         var finalTransaction = new SentryTransaction(transaction);
-        var actualString = finalTransaction.ToJsonString(_testOutputLogger);
+        var actualString = finalTransaction.ToJsonString(_testOutputLogger, indented: true);
         var actual = Json.Parse(actualString, SentryTransaction.FromJson);
 
         // Assert
@@ -278,6 +278,30 @@ public void SerializeObject_AllPropertiesSetToNonDefault_SerializesValidObject()
 
             return o;
         });
+
+        Assert.Contains($$"""
+          "contexts": {
+            ".NET Framework": {
+              ".NET Framework": "\u0022v2.0.50727\u0022, \u0022v3.0\u0022, \u0022v3.5\u0022",
+              ".NET Framework Client": "\u0022v4.8\u0022, \u0022v4.0.0.0\u0022",
+              ".NET Framework Full": "\u0022v4.8\u0022"
+            },
+            "context_key": "context_value",
+            "trace": {
+              "type": "trace",
+              "span_id": "{{context.SpanId}}",
+              "parent_span_id": "{{context.ParentSpanId}}",
+              "trace_id": "{{context.TraceId}}",
+              "op": "op123",
+              "origin": "auto.serialize.transaction",
+              "description": "desc123",
+              "status": "aborted",
+              "data": {
+                "extra_key": "extra_value"
+              }
+            }
+          }
+        """, actualString);
     }
 
     [Fact]