I've just returned with a group of 15 other divers from Mabul/Sipadan and this is my 3rd trip there. If you are going there to dive Sipadan there is a strict limitation imposed by the Malaysian Govt on how many "spaces" each dive operator is allocated daily, and this translates into your actual diving on Sipadan will probably be only one day, and it's also possible that you might not be able to dive there at all.

The dive operators are very reluctant to tell you this until you get there, and this happened to our group and two other groups. Instead, some of them have posted a general statement on the restrictions on their websites, but nothing specific. Make sure you get written confirmation from the dive operator on how many dives you will get on Sipadan (not Mabul) BEFORE you go there.

The consequences of this is that the diving around Mabul (which has no restrictions) is very congested and the quality of marine life is greatly reduced when compared to the last few years.

Sorry for the bad news.