When this text is written, in may 2021 there is a variety of restaurants in Keflavik near B&B Guesthouse. Many are in walking distance, especially those that are on Hafnargata (seen in yellow text box on map).

If you are in the mood for fish you can check out Rain, Duus, Library or Kef restaurant. If you are in the mood for Italian that specialises in pizzas then check out Fernando’s. If you like to choose from pizzas, hamburgers, salat or meat all in one place, then you can check out Antons Mamma Mia.
In to mood for Thai food then check out Thai Keflavik, or do you prefer Cantonese food, then check out Panda. You’ll find a nice little Indian place called Royal Indian and you’ll find a Polish restaurant in the same house as B&B Guesthouse.
If you prefer to grab a kebab you’ll find it at Biryani. There is also a place were you’ll find Middle Eastern cuisine, that one is called Oriento. If you would like to try out a place that sells hoagies then you should visit Olsen Olsen. If you really want a good burger then you’ll find it at Hamborgarabúlla Tómasar or Tommi’s burger joint.

If you are in the mood for something a little more fancy then you should check out Library bistro/bar, Rain, Kef Restaurant or Fiskibarinn that is in Hotel Berg.