Hi Yannick
Bunaken is fine for inexperienced divers, though there's not much to do on the island besides play in the water. Lembeh is not typically a good choice for brand-new divers because it demands excellent buoyancy due to the silty bottom. Save that one for later. On Manado side you actually can do some exploration and see the tarsier monkeys and other wildlife if that's of interest, but there isn't much of what you'd call nightlife, if that's what you're looking for.What are the best dive locations in Indonesia for unexperienced divers? ...Diving is not the only activity we want to employ, but can function as a guide to decide on our travelling locations. We have vistited Bali and Sumatra before, so we want don't want to visit these islands again.
I have read a lot about Bunaken, but I'm still unsure whether it's a good location for beginning divers. The same goes for the Lembeh strait. If I understand it correctly, Lembeh strait is mainly focused on muck diving.
Many of those places are known for wicked currents. New divers are best advised to avoid these kinds of situations until they've got more experience. My advice would be to dive around Bali and then hop on a plane to Labuan Bajo to visit the Komodo park for the dragons. It's really doable.Other locations that I have in mind are Komodo, Flores, Lombok, or other places on Sulawesi.
The coolest big stuff you are likely to see are manta rays, and there are lots of places you can dive with them. For example, at Nusa Penida there's a manta cleaning station in shallow, protected water (called variously Manta Point or Manta Point 2, on the southwest side of the island), and you could go there by speedboat from Bali as a daytrip. Other areas on/near Bali that are easy are the Gilis (near) and Tulamben or Menjangan on Bali.The whole trip is actually still open, so any suggestions would be welcome. Our main interest would be to see the bigger animals in the sea (macro-diving?). My girlfriend definitely wants to see turtles and would like to see some sharks. If it's possible I would like to see some whale-sharks, however I don't know if that's possible since we can only go to a depth of 18 metres.