no you don't need them- well I didn't the last time I went. Always best to check with your doctor though

Have a look here.

http://www.fitfortravel.nhs.uk/destinations/malariamaps/indonesiabali.htm

Glad to see the NHS say no, as I would say no.

cheers guys

I'm a fairly regular visitor to Bali and don't take any medication for Malaria (although I did on our first trip and it made me so sick) However, Dengue Fever is prevalent in Bali and I suggest you take a good tropical strength mozzie repellent and apply it during the day as well as night time. If you can get hold of the Australian 'Bushmans' all the better and brilliant stuff and contains 20% Deet. We used Bushmans in Malarial countries like Vanuatu and never bitten once.
Cheers Geri