We arrived in Semporna and decided to try to learn to dive, so we trawled around for prices to do the PADI open water. The accommodation and course package at Big John's was by far the best value for money, especially for those on a budget. Our instructor Dendy was fantastic - especially as I was a really bad learner, but his patience, mixed with the occasional stern words, got me through the course. The accommodation isn't luxury (don't expect room service or mints on the pillow!), but the rooms have all the basics - four walls, a roof and a bed. We affectionately referred to it as the shack! The people are fatastic and look after you really well, though there isn't a set diving schedule so you are never sure when you are going to be jumping on the boat. After the diving we had some fun times with the guys, singing along to their guitar playing. We enjoyed the place so much we stayed an extra 3 days. The only negative I'd say (and thus is not tied to Big Johns) is in relation to the litter on land and in the sea around Mabul. It is absolutely horrendous. The first thing I saw when I put my head under water was a used nappy! Litter is a serious and unnecessary problem throughout the region and is particularly bad at Mabul. Something needs to be done to reduce litter and clean up the place as it really dimishes the beauty of the island and the experience of being there.