Don't 'need' them, but fins certainly make things easier and will be less tiring. If you are like us, you will want to go everywhere and try the snorkeling at each stop. That can get tiring pretty quick. With fins, you can go pretty effortless all day long.

If you get fins, get the foot form fitting and not strap type.

I feel fins are more like a floatation device. Do you NEED them? no, but I sure like them for safty reason. You start to cough for some unexplained reason and just wiggeling your toes will keep you above water.

There are a lot of nice lightweight shorter snorkel fins out there that arent a big deal to bury in some luggage or stick in shoulder bag for carry on. Dont have to get those long heavy balck rubber fins.

If you find yourself in a current you'll be very happy you wearing fins.

I'd never snorkeled WITHOUT fins. Last time on STJ I developed a blister on my toe, so gave it a try without fins. Yikes, it's a lot of work. I hadn't realized how much more work it is without them.

You could try renting a pair next time if you don't want to buy them and lug them. If you're used to snorkeling without fins, I think you'll be astonished by what they do for you.