Shallow M5.6 earthquake hits offshore Guanacaste, Costa Rica

An earthquake measuring M5.6 was recorded offshore Guanacaste, Costa Rica, at 21:55 UTC on September 30, 2026. The quake occurred at a depth of 10.0 km (6.2 miles), about 84 km (52 miles) southwest of Tamarindo, with coordinates at 9.8°N, 86.4°W.

The location of the epicenter places it offshore in the Pacific Ocean, southwest of the Costa Rican coastline and west of the Nicoya Peninsula. This area is in proximity to several coastal towns, with Tamarindo being the nearest significant population center.

Given the offshore epicenter, critical infrastructure that could be affected includes coastal highways, ports, and regional airports located along the Nicoya Peninsula and adjacent coastal areas.

There is no tsunami threat associated with this earthquake, based on its location and available data.

USGS issued a green alert for this event, indicating a low likelihood of casualties or damage. The maximum estimated intensity for this earthquake was IV, with one felt report submitted. The significance index is 483 (on a scale that runs through 1 000), based on magnitude, felt reports, and estimated impact.

Costa Rica is situated along the boundary between the Cocos and Caribbean plates, making the region prone to significant seismic activity due to subduction-related tectonic processes offshore.

This information was last updated at 22:17 UTC on September 30, 2026.