I get this question a million times: “My goggles leak when I swim. What are the right size goggles for me?” There are a ton of goggles out there in the market of all different shapes and sizes. You want to find a pair that fit into your eye sockets with good suction without the strap over your head. You know then that they fit well into your eye sockets. Once you find a pair like that, you want to wrap the strap higher up on the head onto the “fat part” rather than down near your ears or neck. Tighten the strap so that the slack is taken up in that strap position. If you plan to wear a cap, make sure that you do this fitting with the cap on. If you follow these steps, you’ll be closer to living leak free.
After this point, you’ll want to think about the color of the goggles (if any), tinting, or mirroring. If you are going to be swimming outside, you will certainly want to look at a tinted or mirrored pair of goggles — maybe keep that as an extra one in your bag. I had a member of my Masters team swear by blue goggles as a great indoor and outdoor option.
Finally, color coordination between suit, cap, and goggles seems to be a big issues for some clients of mine. I’ll leave that one up to personal taste.