diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 1d5bdebba4..a1aea6e215 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -57,6 +57,8 @@
         where `package` is different to the package of the current application.
         This wasn't previously documented to work, but is a more efficient way
         of accessing resources in another package than by name.
+    *   Eagerly check `url` is non-null in the `DataSpec` constructors. This
+        parameter was already annotated to be non-null.
 *   Effect:
     *   Improved PQ to SDR tone-mapping by converting color spaces.
     *   Support multiple speed changes within the same `EditedMediaItem` or
diff --git a/libraries/datasource/src/main/java/androidx/media3/datasource/DataSpec.java b/libraries/datasource/src/main/java/androidx/media3/datasource/DataSpec.java
index 2da5d6a095..dea5284fb3 100644
--- a/libraries/datasource/src/main/java/androidx/media3/datasource/DataSpec.java
+++ b/libraries/datasource/src/main/java/androidx/media3/datasource/DataSpec.java
@@ -15,6 +15,7 @@
  */
 package androidx.media3.datasource;
 
+import static androidx.media3.common.util.Assertions.checkNotNull;
 import static java.lang.annotation.ElementType.TYPE_USE;
 
 import android.net.Uri;
@@ -473,7 +474,7 @@ public final class DataSpec {
     Assertions.checkArgument(uriPositionOffset + position >= 0);
     Assertions.checkArgument(position >= 0);
     Assertions.checkArgument(length > 0 || length == C.LENGTH_UNSET);
-    this.uri = uri;
+    this.uri = checkNotNull(uri);
     this.uriPositionOffset = uriPositionOffset;
     this.httpMethod = httpMethod;
     this.httpBody = httpBody != null && httpBody.length != 0 ? httpBody : null;