diff --git a/src/machine/board_wioterminal.go b/src/machine/board_wioterminal.go
index 8132d2ca..ad182c45 100644
--- a/src/machine/board_wioterminal.go
+++ b/src/machine/board_wioterminal.go
@@ -349,8 +349,11 @@ var (
 
 	UART1 = &sercomUSART2
 
-	// RTL8720D
+	// RTL8720D (tx: PC22, rx: PC23)
 	UART2 = &sercomUSART1
+
+	// RTL8720D (tx: PB24, rx: PC24)
+	UART3 = &sercomUSART0
 )
 
 // I2C pins