Spain isn't the best country for vegetarians, France isn't either!
San Sebastián (and the Basque Country) is known for its large number of Michelin starred (*, ** and ***) restaurants. The other restaurants are no better or no worse than anywhere else in Spain, IMO. There are numerous pintxos bars where you may find veggie pintxos.

FYI, Donostia-San Sebastián is NOT a small town!

"Spain isn't the best country for vegetarians, France isn't either!" I guess I missed that at all of the restaurants we've dined at. Vegetarian dishes are on just about every menu and there are number of excellent vegetarian restaurants. Granted, not many, depending on where in Spain you are, but enough to get by if you are a strict vegetarian.

I wouldn't actually consider Donostia-San Sebastián a large town unless you're from a small berg tucked away somewhere in the never lands. At less than 190,000 population, it's half the size of Bilbao, smaller than Pamplona and a whole lot smaller than Antwerp. You can walk across Donosti in a little over an hour, if you're not in a hurry.

I am a vegetarian, but I eat seafood when I travel--so it is easier for me--but while you will not be spoiled for choice, you will not go hungry. Get ready to eat a lot of tortilla (meaning the egg kind) and potatoes. We were not in the mood for fine dining and ate tapas (pintxos) pretty much every night. It will be much more difficult in the smaller towns.

A few resources:
http://www.travelingsolemates.com/sa...-beach-repeat/
http://www.timeout.com/barcelona/tra...-san-sebastian
http://rockinthestove.com/2009/12/26...about-the-pig/
http://www.theperennialplate.com/blo.../04/etxebarri/

@Robert2533
TS wants 'small towns to erxplore'. Then I don't have Donostia-San Sebastián in mind. Hendaye is a small town, as is Saint-Jean-de-Luz (on the other side of the border), as well as my beloved Collioure on the Med. And of course all the locations in the Pyrenées that I mentioned.

Plenty of small villages close to relatively small San Sebastian. You can walk to Paisajes San Juan/Donibane along the beautfiful coastline in 2 hours (10 mins by taxi, 30 mins by bus) or be in Getaria just west of San Sebastian in no time.

Getaria: http://www.euskoguide.com/places-bas...taria-tourism/
Pasajes San Juan/Pasai Donibane: http://www.euroresidentes.com/eurore...s/san-juan.htm

Several excellent seaside restaurants in both Places.

And as Robert says, plenty of food to enjoy in San Sebastian besides meat and fish/seafood.

Ragarding vegetarian food, you should have much fun with the famous pintxos in San Sebastian. Great mushroom pintxos all over and of course delicious cheese. You'll probably like Zeruko: http://www.tripadvisor.com/ShowUserR...e_Country.html

And here are some veggie pintxos and good ideas for places to og:
http://www.todopintxos.com/pintxos/p...83&do=verficha

http://www.todopintxos.com/pintxos/p...50&do=verficha

http://www.todopintxos.com/pintxos/p...90&do=verficha

http://www.todopintxos.com/pintxos/p...40&do=verficha

http://www.todopintxos.com/pintxos/p...82&do=verficha

http://www.todopintxos.com/pintxos/p...65&do=verficha

http://www.todopintxos.com/pintxos/p...29&do=verficha

http://www.todopintxos.com/pintxos/p...78&do=verficha

If your family is vegetarian:

Just select from the menu vegetarian starters, tapas or (in Basque) pintxos, maybe cheese and a dessert. Just skip the main dishes with meat or fish. In every tapas / pintxos bar you will have a good selection of vegetarian food. Tapas / pintxos are usually on display at the bar and you order what appeals to you. If in doubt, just ask what it is.

Tapas / pintxos are usually of three kind: meat, seafood or vegetable. So, it is very easy to eat vegetarian.

If you go to a Michelin-starred restaurant tell them with the reservation that you want a vegetarian set menu. Most restaurants do not have a vegetarian menu but when you ask for it every chef will be very proud to do his best to satisfy you.

Collioure is a nice, small costal village. It's an interesting destination and one of the most attractive villages along the coast, but that is also it's problem. By late July the influx of tourists makes it impossible to get around, as it does on the Costa Brava. If you are not in Collioure by 08:30, finding a place to park is nearly impossible. It's not somewhere I would recommend visiting during the high season of mid-July to early September.

We were there for lunch today, arriving long before the early July tourist hordes started to arrive, and found a nice parking place down at the beach, which we kept until mid-afternoon. By 10:30 this morning people where forced to park at the new parking areas up by the highway, a few kilometers away the beach area.

I have never experience San Sebastian being that crowded during the summer, but it does get rather busy from time to time. St-Jean-de-Luz, which is one of our favorite villages in the Pays Basque does get busy in the summer, especially on market day, but somehow we've always managed to find an empty parking place in the one of the underground parking garages.

Hondarribia, Irun and Hendaye are all classified as small villages, but they are so close to each other that the area has become one major community with only the Bidasoda River separating Hondarribia and Irun from Hendaye. Together the population of the three make them are nearly a large as San Sebastian.