Paying with Debit Card in Resort

Hi, we are taking sterling travellers cheques with us in 4 weeks, was wondering if you can use your Debit Card (not credit card) for paying for extras, e.g. can you pay for excursions with ICR using Debit Card in resort, want to do a couple of trips, just want to see how the boys are with the heat, get used to it before we book. Hoping Hubby will buy a little diamond, well keeping fingers crossed
Really for those things you don't know you want until you see them. Thanks for any advice.
