diff --git a/tstest/natlab/natlab.go b/tstest/natlab/natlab.go
index df2611be4..2d3f3ae70 100644
--- a/tstest/natlab/natlab.go
+++ b/tstest/natlab/natlab.go
@@ -26,7 +26,6 @@
 	"sync"
 	"time"
 
-	wgconn "github.com/tailscale/wireguard-go/conn"
 	"inet.af/netaddr"
 )
 
@@ -759,8 +758,7 @@ func (c *conn) canRead() error {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	if c.closed {
-		// TODO: when we switch to Go 1.16, replace this with net.ErrClosed
-		return wgconn.NetErrClosed
+		return net.ErrClosed
 	}
 	if !c.readDeadline.IsZero() && c.readDeadline.Before(time.Now()) {
 		return errors.New("read deadline exceeded")