Does HoloSwim 3 Pro have built-in GPS?

Yes. The goggles have their own GPS receiver and digital compass, so open-water pace, distance, and route tracking don’t require pairing with a watch.

Does HoloSwim 3 Pro support heart rate monitoring?

Not from a sensor built into the goggles. It is designed to pair with HoloSport’s wrist-worn HandPlus B2 monitor, which can also be clipped to a swim cap, though HoloSport lists that pairing as expected for September 2026 rather than confirmed live.