Depends on your definition of "upscale hotels". No there is no Hilton or Sheraton but it would kill me to stay in such a place on a diving trip anyway. Mozambique essentially divides into three main diving areas;
1. Southern Mozambique which Jan Kruger refers to and which is just a chip and a putt from the Kruger National Park. I'll say a little something more about this area in a while.
2. South Central Mozambique is a hard drive, or a flight away but has awesome diving. Here I'm referring to Inhambane, Pomene, Vilanculos, Bazaruto islands etc.
3. Northern Mozambique (the Querimba archipelago) is very far and requires two flights (one to Pemba and another chartered flight to one of the islands). I don't know a great deal about diving there but I understand that places like
Vamizi Island are probably as upscale as you are likely to find in Mozambique (with a price tag to match).
For the moment, let's return to Southern Mozambique. There are basically three places where one could go diving. They're all within easy reach of the South African border but would require some 4x4 or high ground clearance driving through soft sand. Most of the operators offer some sort of shuttle service anyway so it's really easily accessible.
1. Ponta do Ouro is town at the very southern tip of Mozambique. It's a very popular destination for South African divers but personally I'm not mad about it. Don't get me wrong, the diving is awesome but it's a very bustling place and sometimes just too crowded for my liking. Like I say, it's a town, not a lodge or resort. There are a number of lodges or dive camps and two that I can quickly think of are;
Simply Scuba
Devocean Diving
2.
Ponta Malongane is a little bit further north and I prefer it over Ponta do Ouro by far. It is not a town but a fairly large resort with a dive camp. There are all sorts of types of accommodation, ranging from camping to chalets, none of which are particularly luxurious but most of it quite sufficient. It can also get rather busy but not quite as hectic as Ponta do Ouro.
3.
Ponta Mamoli is another resort that's a little bit further north still. I've been there to see what it looks like but never stayed or dived there. It is lovely though and, if you're looking for something upscale and willing to pay a little more, I can't imagine that you'd be able to do better than Ponta Mamoli. The fact that it is more expensive and more exclusive means that it is less of a circus than the other two and I should think it must be the perfect place to spend a honeymoon (or part thereof).
Let me know if you have any more questions or if you want to know more about South Central Mozambique as that's a whole different chapter altogether and would've made this posting too long.