diff --git a/bigtable/bigtable.go b/bigtable/bigtable.go
index 0313070c8cfb..ef45d508268c 100644
--- a/bigtable/bigtable.go
+++ b/bigtable/bigtable.go
@@ -88,6 +88,8 @@ func NewClientWithConfig(ctx context.Context, project, instance string, config C
 	// Attempts direct access to spanner service over gRPC to improve throughput,
 	// whether the attempt is allowed is totally controlled by service owner.
 	o = append(o, internaloption.EnableDirectPath(true))
+	// Allow non-default service account in DirectPath.
+	o = append(o, internaloption.AllowNonDefaultServiceAccount(true))
 	o = append(o, opts...)
 	connPool, err := gtransport.DialPool(ctx, o...)
 	if err != nil {