Lloret de Mar at Night.
Tossa de Mar, is more of a family resort, with lot's of nightime entertainment, being provided by Hotels. The nearby town of Lloret de Mar, is a different scene all together.
If your looking for Open all night bars, then Tossa de Mar, is not for you. You are more likely to get a quiet night in a restaurant, than spend the midnight hours, drinking and dancing away.
Trip Advisor, has some great comments from people who have visited Tossa de Mar, in recent years. Most people have the same view, stay in Tossa de Mar for it's nice restaurants, and have a trip over to Lloret de Mar, for the Nightclubs. Lloret de Mar, is not getting the kindest of reviews, with one person saying its "Nasty".
Tossa de Mar Nightlife does exist, but it's not for the 18 to 30's.