Haney, Novick and Cardy send Robin, Aqualad, Wonder Girl and Kid Flash to the beach for spring break in Teen Titans 9 (May/June 1967).
We get to see the exterior of Titans Lair in this issue, as they fly their helicopter out, the entrance concealed by a billboard for the Batman tv show. The Titans have had their presence requested in Baxter Beach, which is the site of an annual brawl between students from two rival universities.
Both universities have asked the Titans to be on their side, and sent them t-shirts. Wonder Girl creates her own Teen Titans t's so they can be neutral. They get between the students, and manage to get them all working together to build a jetty to restore the eroding beach.
The a pirate guy, Captain Tiger, rams his submarine right into the jetty. The story needed someone for the team to fight against, since they were being peacemakers with the kids.
And it allows for all the rowdy college kids to join the Titans in the big final beach battle against Captain Tiger and his men. For protecting the town, and building the jetty to restore the beach, the townspeople of Baxter Beach also decide the college kids aren't so bad after all.