San José: As the nation's capital, the Central Valley enjoys Costa Rica's most robust 4G and LTE coverage. Signal is strong across downtown, popular districts like Escazú and Barrio Escalante, and at Juan Santamaría International Airport (SJO). Indoor coverage in hotels and malls is generally good. The inter-urban train system is entirely above-ground, providing a consistent signal during travel between cities like Heredia and Cartago.

La Fortuna: In the town center, the base for visiting Arenal Volcano, you'll find reliable 4G service. Connectivity becomes less predictable as you venture out to the area's famous hot springs, remote eco-lodges, and hiking trails. Expect signal to be spotty or non-existent in dense rainforest sections and on the higher slopes of the volcano.

Tamarindo: This bustling Guanacaste beach town has strong 4G and LTE coverage along its main strip and popular beachfront areas. Most hotels and restaurants offer good indoor reception. The signal may weaken if you travel to more isolated beaches or into the rural countryside just outside the immediate town limits.

Manuel Antonio & Quepos: The service town of Quepos and the main road through the tourist area of Manuel Antonio have dependable 4G coverage. Inside Manuel Antonio National Park itself, the signal is inconsistent- you will likely have service near the entrance and on the main, crowded beaches, but it drops off quickly on the less-trafficked jungle trails.

Puerto Viejo de Talamanca: This Caribbean hotspot has solid 4G coverage in the main town area and along the coastal road to nearby beaches like Playa Cocles. However, the signal can be less reliable inside buildings with thick walls and will degrade significantly as you head inland or towards more remote areas like the Gandoca-Manzanillo Wildlife Refuge.

Major Highways: Coverage is strong along Route 27 (Autopista José María Castro Madriz) connecting San José to the Pacific coast and on the Inter-American Highway (Route 1) within the Central Valley. Expect frequent signal drops and dead zones on Route 32 through the dense rainforest of Braulio Carrillo National Park and on the Inter-American Highway (Route 2) over the high-altitude Cerro de la Muerte.

Incofer Commuter Train: This rail system operates primarily within the Greater Metropolitan Area, linking San José, Heredia, Alajuela, and Cartago. Because it travels through the most populated part of the country, cellular service is consistently reliable for the entire duration of these short-distance trips.

Mountain Passes: Driving through high-altitude areas will result in significant signal loss. The pass over Cerro de la Muerte (Route 2) is a well-known dead zone where connectivity is unavailable for long stretches. Similarly, roads through the Tilarán Mountain Range near Monteverde and Arenal have intermittent and unreliable service between towns.

Highway Tunnels: You will lose all mobile signal when transiting through the Zurquí Tunnel on Route 32. Service drops upon entry and is restored only after exiting the tunnel. Shorter tunnels on other routes will also cause brief but complete interruptions in connectivity.

Remote Regions: Expect very limited to no service in large parts of the Osa Peninsula, particularly within Corcovado National Park. The Nicoya Peninsula also has spotty coverage away from main tourist towns like Santa Teresa or Tamarindo. Rural areas along the northern border with Nicaragua often lack consistent signal.