We do bring some US cash to get us started (enough to pay for the airport transfer and a bunch of small bills for tips). However we mostly use a debit card and withdraw the maximum amount of J dollars every few days from a ScotiaBank ATM. I wouldn't use a debit card as an credit card anywhere in Jamaica, except for maybe a few reputable places (like Ivan's, Rockhouse, etc.). In the event of theft/fraud, you would be losing your actual money, not credit. Plus I think my bank might charge additional fees if I use my debit as a credit card, while abroad.