Can I use my M430 when swimming?
Yes, your M430 is suitable for swimming and bathing.
When you're recording a swimming session with your M430, water may prevent the wrist-based heart rate measurement from working optimally. But the M430 will still collect your activity data from your wrist movements when swimming.
Note that you can't use a Polar heart rate sensor with a chest strap with the M430 when swimming because Bluetooth doesn't work in water.
For more detailed information on the water resistance of your running watch, see the M430 eManual.