Four men held up the Coopeservidores credit union in Grecia Friday afternoon, and police detained four suspects almost immediately.
Some local expats expressed shock that this had happened in their town.
Fuerza Pública officials credited the current system of patrols for detaining the four almost as the 911 emergency call was being logged.
The amount of money taken from the financial institution had not been computed, but patrons told police that the robbers had taken some of their possessions too.
Meanwhile, judicial agents in Playa La Penca de Santa Cruz also Friday detained three men who are accused of breaking into the vehicles of tourists in the area. Agents had been following the men because they were suspects in earlier similar crimes at other beaches, they said.