diff --git a/variants/um_feathers3/pins_arduino.h b/variants/um_feathers3/pins_arduino.h
index 8de87c688a9..1c81339c88e 100644
--- a/variants/um_feathers3/pins_arduino.h
+++ b/variants/um_feathers3/pins_arduino.h
@@ -16,6 +16,10 @@ static const uint8_t RX = 44;
 static const uint8_t SDA = 8;
 static const uint8_t SCL = 9;
 
+#define WIRE1_PIN_DEFINED 1  // See Wire.cpp at bool TwoWire::initPins(int sdaPin, int sclPin)
+static const uint8_t SDA1 = 16;
+static const uint8_t SCL1 = 15;
+
 static const uint8_t SS = 5;
 static const uint8_t MOSI = 35;
 static const uint8_t MISO = 37;