We have done both......brought our own and used the ones provided on excursion boats. In Puerta Vallarta the masks looked so old and beat up, but guess what, they worked great/didn't leak. My son has a narrow face and we went through so many masks before buying him one, but, in Belize, he used one on the boat, and, again, no leak! We never pack fins, though. Too much to carry for 4 people!