diff --git a/posts_create.go b/posts_create.go
index 7c9001b..fc389f1 100644
--- a/posts_create.go
+++ b/posts_create.go
@@ -138,6 +138,14 @@ func (c *Client) CreateCarouselPost(ctx context.Context, content *CarouselPostCo
 		return nil, err
 	}
 
+	// Wait for all child containers to be ready before creating the carousel container
+	// The Threads API requires child containers to be in FINISHED status
+	for i, childID := range content.Children {
+		if err := c.waitForContainerReady(ctx, ContainerID(childID), DefaultContainerPollMaxAttempts, DefaultContainerPollInterval); err != nil {
+			return nil, fmt.Errorf("child container %d (%s) not ready: %w", i+1, childID, err)
+		}
+	}
+
 	// Create container first
 	containerID, err := c.createCarouselContainer(ctx, content)
 	if err != nil {
diff --git a/tests/integration/integration_test.go b/tests/integration/integration_test.go
index 872d008..a079671 100644
--- a/tests/integration/integration_test.go
+++ b/tests/integration/integration_test.go
@@ -341,8 +341,7 @@ func TestIntegration_PostOperations(t *testing.T) {
 		}
 		t.Logf("Created second media container: %s", container2)
 
-		// Wait a moment for containers to be ready
-		time.Sleep(1 * time.Second)
+		// Note: No sleep needed - CreateCarouselPost waits for child containers to be ready
 
 		// Create carousel post
 		content := &threads.CarouselPostContent{
@@ -681,7 +680,7 @@ func TestIntegration_SpoilersAndTextAttachments(t *testing.T) {
 			return
 		}
 
-		time.Sleep(1 * time.Second)
+		// Note: No sleep needed - CreateCarouselPost waits for child containers to be ready
 
 		// Create carousel with all media marked as spoilers
 		content := &threads.CarouselPostContent{