The currency used in Port el Kantaoui is the Tunisian dinar.
You'll need to exchange your pounds for dinar when you get to Port el Kantaoui, and back again before you travel home. It's a closed currency, making it illegal to carry it in or out of Tunisia. There are lots of places to exchange your money during your holiday, plus ATMs. And you can use your credit or debit card too (Visa is the most reliable option).
While you can't get your dinar from Thomas Cook Travel Money, it's a great option for your future travels. Think competitive rates, delivery to you at home or work, and a range of more than 50 currencies – that's more than 98% of destinations covered! Or, if you're looking for a simple and secure way to spend, you can't go wrong with the Caxton currency card.