Oceans & Turtles · Tamarindo and Santa Teresa, Pacific coast

Beachfront Lights and Sea Turtles: Why Costa Rica's Beaches Need Dark

Marine biologist Daniel Arauz of the turtle group CREMA says lights and noise from coastal development have cut sea turtle nesting at busy Pacific beaches like Tamarindo and Santa Teresa, based on his field observations, The Tico Times reported on Oct. 25, 2026. The science behind the warning is well established: artificial light draws hatchlings inland and can deter nesting females, and simple shielding helps.

By Pura-Verde.com Editors · Published October 30, 2026
Original report: The Tico Times: Beachfront Lights Are Driving Sea Turtles Away From Costa Rica's Nesting Beaches (2026-10-25)

A baby sea turtle's first job is to find the ocean, and it does that by crawling toward the brightest horizon. On a natural beach at night, that's the sky over the water. On a beach lined with hotels, restaurants and streetlights, it can be a parking lot. That simple problem is at the heart of a warning from Costa Rican marine biologist Daniel Arauz, as The Tico Times reported on Oct. 25, 2026.

What Daniel Arauz is seeing on Pacific beaches

Arauz works with CREMA, the Rescue Center for Endangered Marine Species, a Costa Rican nonprofit founded in 2012 that monitors sea turtles and runs nesting-beach projects on the Nicoya Peninsula. He told The Tico Times that coastal development has reduced nesting at Tamarindo and Santa Teresa, two of the Pacific coast's busiest surf towns.

That view comes from his field observations, not a published long-term nest count, and The Tico Times noted that other factors could also be at play. Nobody has put a number on how much nesting has dropped at those beaches. But the mechanism he describes is well documented.

Sea turtles tend to come back to nest near the beach where they hatched, a behavior scientists call natal philopatry. Arauz explained that when a female can't nest there, she looks for another beach, and that bright light or heavy noise can make her turn around and go back into the sea without laying eggs.

What the science says about light

The U.S. agency NOAA, which manages sea turtle recovery in American waters, says artificial light on and near nesting beaches can deter females from coming ashore and disorients hatchlings, which often crawl inland instead of toward the ocean. Its loggerhead turtle page sums up the advice in one line: "Keep nesting beaches dark and safe at night."

A hatchling that heads the wrong way can end up on a road or in someone's yard, or simply run out of energy before it reaches the water, easy pickings for crabs and birds.

Costa Rica has its own evidence. On the Caribbean side, a Duke University analysis found fewer green turtles came ashore on the brightest stretches of Tortuguero's beach, near the village. In March 2023, the national electricity company, ICE, installed 71 red-light lamps in Tortuguero, and a later study reported by The Tico Times found hatchlings were far less likely to crawl toward red lamps than toward white ones.

Why it matters beyond the turtles

Turtle nests carry ocean nutrients onto the sand. Studies in Florida and South Africa, cited by The Tico Times, found that dune plants and ghost crabs take up nutrients from turtle eggs, and eggs and hatchlings feed birds and crabs. How much that matters on Costa Rica's beaches hasn't been measured, but fewer nests means less of that flow from sea to land.

There's also the obvious traveler angle. Watching a turtle nest or a hatchling run is one of the most memorable things you can do in Costa Rica, and it depends on beaches staying dark enough for turtles to use them.

What hotels, homes and visitors can do

Arauz's recommendations, as reported by The Tico Times, are practical and cheap:

• Keep building lights from shining onto the beach.
• Shield light fixtures so the bulb isn't visible from the sand.
• Avoid large illuminated screens facing the sea.
• Keep nighttime noise and activity on the beach to a minimum.

NOAA and other U.S. wildlife agencies give similar advice to beachfront owners: turn off, shield or redirect any light that's visible from a nesting beach. Long-wavelength red or amber lighting, like Tortuguero's, is another option.

For visitors, the rules are simple. Don't use flashlights, phone lights or flash photography on a nesting beach at night. Don't approach or touch turtles or hatchlings. If you want to see nesting, go with a certified local guide or a recognized conservation project rather than on your own; they know when and where it's appropriate. Arauz stressed responsible tourism that lets people watch without disturbing nesting, and The Tico Times noted that crowds at Ostional have kept turtles from nesting in the past.

Where to see turtles responsibly

Pacific beaches host olive ridleys, including the mass nesting events called arribadas at Ostional, which we covered in our report on one of 2026's biggest arribadas. On the Caribbean side, leatherbacks arrive each spring. Our map lists sea turtle projects that run guided programs and welcome volunteers, and our guide to sea turtle conservation in Costa Rica explains how to choose one.

Santa Teresa sits near the southern tip of the Nicoya Peninsula, in the same Cóbano district as Montezuma, where a different pressure from development is in the news: residents and musicians are protesting hillside clearing near Montezuma waterfall, a separate case that SINAC documented and prosecutors are investigating.

Frequently asked questions

Why are lights bad for sea turtles?

Hatchlings find the ocean by heading toward the brightest horizon. Artificial lights can lead them inland, and NOAA says lighting near beaches can also discourage females from coming ashore to nest.

Are sea turtles nesting less at Tamarindo and Santa Teresa?

Marine biologist Daniel Arauz of CREMA says development has reduced nesting there, based on his field observations. No published long-term nest count has measured the decline.

What is turtle-friendly lighting?

Lighting that can't be seen from the beach: fixtures that are shielded, aimed down and away from the sand, kept low, or switched off during nesting season. Red or amber long-wavelength lights are less disruptive than white ones.

Can I watch sea turtles nest in Costa Rica?

Yes, but go with a certified local guide or a recognized conservation project, keep lights off and stay back from the turtles.

Sources and original reporting

1. The Tico Times: Beachfront Lights Are Driving Sea Turtles Away From Costa Rica's Nesting Beaches (2026-10-25)
2. NOAA Fisheries: Loggerhead Turtle
3. CREMA
4. Global Diversity Foundation: Daniel Emil Arauz Naranjo profile

We wrote this story from the published reports and official sources above. We didn't interview the people named unless the story says so.