ABSOLUTELY, YES.
Bring shoes that can get sandy & wet. Teva-style hiking sandals or water shoes are ideal. DON'T under any circumstances hike in flip flops :) Other than that, bring a towel, bathing suit, shorts...beachy things!
If the Groom/Bride didn't assign you a place, check out our 'Hotel & Accommodations' list on the "Travel & Stay" page of this website.
ASAP please! The sooner the better, really!