diff --git a/sentry-ktor-client/build.gradle.kts b/sentry-ktor-client/build.gradle.kts
index a28c11eab8d..b4a5cecb05b 100644
--- a/sentry-ktor-client/build.gradle.kts
+++ b/sentry-ktor-client/build.gradle.kts
@@ -44,6 +44,31 @@ dependencies {
   testImplementation(libs.okhttp.mockwebserver)
 }
 
+testing {
+  suites {
+    register<JvmTestSuite>("testKtor300") {
+      useJUnit()
+      dependencies {
+        implementation(enforcedPlatform("io.ktor:ktor-bom:3.0.0"))
+      }
+      sources {
+        java.setSrcDirs(sourceSets.test.get().java.srcDirs)
+        resources.setSrcDirs(sourceSets.test.get().resources.srcDirs)
+      }
+    }
+  }
+}
+
+configurations.named("testKtor300Implementation") {
+  extendsFrom(configurations.testImplementation.get())
+}
+
+kotlin.target.compilations.named("testKtor300") {
+  associateWith(kotlin.target.compilations.getByName("main"))
+}
+
+tasks.check { dependsOn(testing.suites.named("testKtor300")) }
+
 buildConfig {
   useJavaOutput()
   packageName("io.sentry.ktorClient")
diff --git a/sentry-ktor-client/src/main/java/io/sentry/ktorClient/SentryKtorClientPlugin.kt b/sentry-ktor-client/src/main/java/io/sentry/ktorClient/SentryKtorClientPlugin.kt
index 0e4538fb418..0109aeb9fbc 100644
--- a/sentry-ktor-client/src/main/java/io/sentry/ktorClient/SentryKtorClientPlugin.kt
+++ b/sentry-ktor-client/src/main/java/io/sentry/ktorClient/SentryKtorClientPlugin.kt
@@ -7,6 +7,7 @@ import io.ktor.client.request.*
 import io.ktor.client.statement.*
 import io.ktor.util.*
 import io.ktor.util.pipeline.*
+import io.ktor.util.reflect.TypeInfo
 import io.sentry.BaggageHeader
 import io.sentry.BuildConfig
 import io.sentry.DataCategory
@@ -98,9 +99,13 @@ public val SentryKtorClientPlugin: ClientPlugin<SentryKtorClientPluginConfig> =
 
     // Attributes
     // Request start time for breadcrumbs
-    val requestStartTimestampKey = AttributeKey<SentryDate>("SentryRequestStartTimestamp")
+    val requestStartTimestampKey =
+      AttributeKey<SentryDate>(
+        "SentryRequestStartTimestamp",
+        TypeInfo(SentryDate::class, null),
+      )
     // Span associated with the request
-    val requestSpanKey = AttributeKey<ISpan>("SentryRequestSpan")
+    val requestSpanKey = AttributeKey<ISpan>("SentryRequestSpan", TypeInfo(ISpan::class, null))
 
     onRequest { request, _ ->
       val effectiveScopes = if (forceScopes) scopes else Sentry.getCurrentScopes()