Hello Julien
I worked 3 years in the Maldives (1 year in resorts, 2 years on a local island) so I'm going to try to give you some input.
There are 3 type of islands in the Maldives:
- resort islands = 1 (tiny) island IS the hotel. Nothing else than the resort.
- deserted island = absolutely nothing on it, most of the time owned by someone though, so you cannot go there just because you have a boat and you want to go.
- local islands (opened for a few year to the tourism; before, a foreigner needed an authorisation to go on a local island) = where the maldivian people live.
Usually small villages, unless you are in Male (the capital) which is not the nicest city on earth (very crowded and noisy, very densily populated: more than 200 000 people on 2km square o_0 )
Very quiet
I honestly doubt you are going to find a cheap DM course on a resort, because I doubt that, unless you know someone overthere, a dive centre is going to provide accommodation and food. If you have to pay for it, it's going to come very pricey very quickly. Understand that most of the resort island are tiny (15-20 min to walk around after a good meal, I'm not joking) thus the space for the staff is limited and it's not likely that there will be a spare room for a DMT.
Again, on a resort island, there is nothing else that the hotel. You cannot walk a little bit further and find a cheaper accommodation or cheaper food.
Local island would come cheaper (unless it's Male, the capital) now that they are open to tourism. Be carefull chosing the dive centre though, there are a lot of cowboys available.
However, understand that, as a 100% muslim country, there is NO alcohol available on local island (different rules apply to resort islands.)
There are also no mall, no cinema/library, no nightlife etc etc. Even in Male, the choices are very limited.
Be aware that if you come on a tourist visa, Maldives don't work like many other country is SE Asia. You don' go in and out, and in and out in order to renew your tourist visa and be able to stay more.
Tourist visa is one month,
eventually renewable but not garanteed.
Working visas in the diving industry in the Maldives are ONLY for instructors; it's actually illegal to employ a foreign DM.
I know a sponsorship visa exists, but I don't know exactly for who and how it works. What I do know is that, except for tourism visa that are sort out on arrival, you CANNOT start a process for a working or sponsorship visa from inside the country. It has to be sort out before your arrival, or you will have to leave the country and wait until your visa is ready.
Diving is beautiful overthere, strong currents and bif "stuff". But it's not a cheap country.
I cannot recommend a good dive centre on a local island, the only one I knew well was the one I owned and managed, but it's not the case anymore
I know there are more and more opening every year though, maybe you can find one that suit your need.
But I would recommend to sort everything out before going there, or you might find yourself short on time with the visa. Also, in December, it's high season, so better to have something booked or you might find yourself with nowhere to stay; it can be fully booked.
It's quite difficult and pricey to travel from island to island or from atoll to atoll and really well organised for the tourists that are with a hotel:
- close to Male, by boat (dhoni, usually cheaper) or speedboat (speedboats come more expensive due to fuel consumption, and fuel is not cheap overthere)
Some ferries do exist but they don't go everywhere (some do longer journey) and good luck with finding out when they leave for real ^_^ and it will not be be a comfortable journey at all, not for 15hours (Male, Laamu atoll in the southern atoll, it's what it takes if the weather is good. No toilet, no water, no food on board, it take organisation ^_^ )
- sea planes
- domestic planes
These 2 last options are expensive, specially for tourists.
I'm not trying to put you off, only to make things more realistic...
Enjoy anyway, hope that helps and best of luck.