Question about Garmin Hrm-Tri

Unfortunately, I cannot answer whether the strap works with the Vivoactiv 3 Music.

If you want to swim in the pool, it is recommended to use the HRM-SWIM, which is this blue belt. The HRM-TRI will slide off every time you push off the edge of the pool. It's made to be worn under a triathlon suit. I have both belts and would like to sell them again because I have stopped triathlon.