no, you cant use your Travelex prepaid card in Cuba im afraid. This is because Cuba wont accept anything American, and the cards are either visa or mastercard. they wont accept travellers cheques either for the same reason. if you try to exchange dollars to pesos you will be charged something ridiculous like 20% commission !!!!
you have to exchange £££ while you are there to peso, but be careful because the unscrupulous folk out there know you will have cash on you xxx

"... This is because Cuba wont accept anything American, and the cards are either Visa or Mastercard. They wont accept travellers cheques either for the same reason..."

That is ALL incorrect info. Many non-US affiliated Visa and Mastercards are accepted and American Express Traveller's Cheques are fine too.

Tommo: Have a read through this:

http://www.tripadvisor.com/Travel-g147270-c109329/Cuba:Caribbean:Money.Exchange.html

Have fun.

Cheers,
Terry

Of all the many times we have been to Cuba, we have never had a problem with Master Card or Visa. We were there two years ago and at that time they would NOT accept an American based card.

We found i t very safe. Just don't act like an arrogant foreigner and try to speak a little Spanish

Anna, read my link above. It explains almost everything you need to know about Money Exchange and as you'll see the Post Office Card is no problems.

That said, you should NEVER depend on just one source of money in a developing country - especially one with a horrible telecommunications infrastructure like Cuba. Cash is king.

Cheer,
Terry