If you are on the coast and an earthquake is so strong you can barely stand, or it lasts unusually long, head for high ground as soon as the shaking stops. Do not wait for an alert. A tsunami from a quake off Costa Rica’s coast can reach parts of the shore in about five minutes, faster than any official warning can travel.
That is the core rule from Costa Rica’s National Tsunami Monitoring System, known as SINAMOT, which operates from the Universidad Nacional with the University of Costa Rica. Its message after strong coastal quakes is blunt. If you felt the shaking very strong or very long, evacuate now, because the tsunami can arrive before its report does.
The reason is timing. Seismic data usually reaches the monitoring team about 15 minutes after a quake, and analyzing it and issuing a report takes roughly 10 more. When a magnitude 7.7 earthquake struck Panama on Oct. 9, SINAMOT ruled out a threat to Costa Rica 22 minutes after the shaking began. That is fast for a scientific assessment and far too slow if a local wave is already on its way.
Protect yourself first while the ground is moving. Drop, take cover and hold on until it stops, as you would in any Costa Rica earthquake. Then move. After a strong quake, SINAMOT advises getting at least 5 meters (16 feet) above sea level or 1 kilometer (0.6 miles) inland. Higher and farther is better. If authorities order an evacuation for a large tsunami, the safe line rises to 20 meters (66 feet) above sea level.
Go on foot if you can as a strong quake can crack roads, bring down power lines and block the only street out of a beach town, and a line of cars can trap everyone in it. Walking uphill is often faster. If there is no high ground within reach, go up instead. The upper floors of a sturdy concrete building are the fallback when you cannot get out of the low zone in time.
Learn the ocean’s own warnings. The sea may suddenly pull back and expose the seafloor, rocks or stranded fish. You may hear a loud roar from the water, like a train or a jet engine. Either one means a wave is coming. Do not walk out to look, because the water that left comes back fast.
Keep away from rivers and estuaries. A tsunami pushes up river mouths and can flood far inland along the banks, so choose a route that leads away from them. The first wave is rarely the last. Tsunamis arrive as a series, and a later wave can be the largest. The Pacific Tsunami Warning Center warns that the danger can last many hours after the first wave, so stay on high ground until authorities give the all-clear.
Not every tsunami starts close by. A quake off Mexico, South America or across the Pacific gives you hours, not minutes. A wave from the trench off Colombia and Ecuador takes about two hours to reach Costa Rica, and one from near New Zealand takes about 15, according to SINAMOT. In those cases you will hear from authorities first. SINAMOT assesses the threat, and the National Emergency Commission (CNE) decides what the public is told to do. Both post updates on their social media accounts.
SINAMOT uses three threat levels, and each one tells you what to do.
- Low means dangerous currents and sudden changes in sea level, but no flooding. Get out of the water and stay out until the alert is lifted.
- Medium means minor flooding is possible. Leave the beach and any area less than 5 meters (16 feet) above sea level, shown in orange on tsunami evacuation maps.
- High means major flooding is possible. Leave any area less than 20 meters (66 feet) above sea level, shown in yellow on the maps, or move to the upper floors of a safe building.
The low level is the one you are most likely to see. After the magnitude 8.8 earthquake off Russia’s Kamchatka Peninsula in July 2025, the CNE put the entire Pacific coast on yellow alert and asked people to stay out of the water the next morning. The waves did not flood the coast. Still, the CNE noted that currents from earlier distant tsunamis, including Japan’s in 2011 and Tonga’s in 2022, caused boat collisions in Costa Rica. A low threat does not mean it is safe to swim.
If you have a boat and authorities give more than three hours’ notice, SINAMOT says vessels on land or at anchor can be taken out to water at least 100 meters (330 feet) deep, where tsunami waves are much smaller. With less time than that, leave the boat and get to high ground.
Find your zone before you need it. SINAMOT publishes an interactive tsunami evacuation map where you can check whether your home, hotel or workplace sits in a flood zone. Maps exist for a growing number of coastal communities, though not all of them. When you arrive somewhere new on the coast, walk the evacuation route once so you are not guessing in the dark.
Some towns have gone further. By 2024, 11 Costa Rican communities had earned Tsunami Ready recognition from UNESCO’s Intergovernmental Oceanographic Commission, which requires mapped hazard zones, posted routes and regular drills. Tamarindo, Sámara and Playas del Coco are among them, and Cahuita became the first on the Caribbean coast in June 2024.
Make a family plan that covers tsunamis. Decide where you will go from home, work and school, and where you will meet if phones are down. Keep a small bag by the door with water, a flashlight, medicines and copies of your documents. SINAMOT has urged families to use Costa Rica’s national evacuation drill to practice that plan.
Both coasts are at risk. Costa Rica sits on the Pacific Ring of Fire and has recorded at least 45 tsunamis since 1746 on its Pacific and Caribbean shores, according to UNESCO’s oceanographic commission. The 1991 Limón earthquake sent a tsunami ashore that killed two people at Boca Matina, and the 1992 Nicaragua quake produced waves several meters high along Costa Rica’s northern coast, according to SINAMOT coordinator Silvia Chacón.
Most tsunamis are set off by undersea earthquakes, though landslides can cause them too. In July 2024, SINAMOT linked a small tsunami at Punta Burica, on the Panama side of the border, to an undersea landslide after a magnitude 6 quake. Even a moderate quake near the shore deserves respect.
Damaging tsunamis are rare here, and most alerts end with nothing worse than strong currents. The minutes after a strong quake on the coast are the exception. If the ground shakes hard while you are near the sea, do not wait to be told. Move to high ground.
This guide was updated Oct. 23, 2026, with current guidance from Costa Rica’s tsunami monitoring system.
