Moyo may well have some beautiful beaches, a stunning waterfall and some top snorkelling, but getting here is a bit of a hassle. You basically have three options: speedboat (very expensive but fast), slowboat (moderately expensive but slow) and public boat (cheap but departs randomly).
Boats depart from the fishing hamlet of Ai Bari, which is about a 45-minute drive or ride north of Sumbawa Besar.
If you're interested in a daytrip to Moyo, you have two options: fast and slow. We were quoted a staggering 3,700,000 for a speedboat (which takes 30 minutes to reach the Amanwana and 45 minutes to get to Labuan Aji). Slowboats range from around 800,000 rupiah to 1,500,000 (depending on the size of boat, your negotiating ability and other random factors) and take 1.5 hours to reach the Amanwana and two hours to reach Labuan Aji. This means if you want to do a daytrip to Moyo on the slowboat you need to leave Sumbawa Besar early to get your money's worth on the island as it is two hours each way by boat, plus an hour hike each way to the waterfall - so six hours before you have actually done or seen anything! Plan accordingly.
If you are lucky enough to have more time in Sumbawa, the good news is the local boat costs 50,000-70,000 rupiah and takes around two hours to reach Labuan Aji. The bad news is it has no schedule and runs just "when the villagers want to get supplies". This creates two problems. The boat may not leave for Moyo on the day you want to go, and then you may end up stranded on Moyo for longer than you planned because the boat isn't returning for a few days.
Until a more affordable scheduled boat becomes available, this situation will limit how many independent travellers visit the island. While the waterfall and the snorkelling are both outstanding, a million rupiah is a lot to pay and the chances of you randomly meeting another traveller in Sumbawa Besar to share costs is quite low. There is a lot of land speculation on Moyo as of 2016 though, so we imagine when more places to stay appear, the boat system may get a bit more reasonable.
A fourth option is to take an organised tour. Contact travel agencies in Sumbawa Besar for more information - your best chance will be on weekends and over holiday breaks when domestic travellers may be booking trips in sufficient numbers and you maybe able to join in.