No worries, you can get both pizza and hamburgers in Åland

There isn't a single McDonald's in Åland. But there are several pizzerias and hamburger restaurants in Mariehamn. The Finnish chains Hesburger and Koti Pizza can be found in the town centre.
If you want a pizzeria with more of a restaurant feel, you can go to Adlon Pizzeria & Sportsbar at the Hotel Adlon.
At Ali´s Kebab or Gatuköket Draken by the ferry terminal you can get kebab.
Outside Mariehamn it is easier to find places to eat in the summer. If nothing else is open, you will usually be able to pick up something to eat at a petrol garage shop.