Hua Hum: Argentina's Low-Altitude Lake Crossing

Hua Hum sits at 685 meters above sea level, making it the lowest international pass in the Patagonian Andes. That low elevation keeps the route open almost year-round, even when snow closes higher crossings like Cardenal Samoré. The pass links San Martín de los Andes to Panguipulli, Chile, but not by road alone — the final leg is a 1.5-hour ferry ride across Lago Pirehueico.

Getting There and Crossing the Border

The Approach from San Martín de los Andes

The drive covers 47 to 60 kilometers along Provincial Route 48, depending on where you measure from. The first stretch is paved, then turns to gravel that holds up well in dry weather — a standard two-wheel-drive car manages fine. You'll pass the Bandurrias viewpoint shortly after leaving town; stop for the photo, because the road narrows and climbs after that. The route skirts the northern shore of Lago Lácar, cutting through coihue and raulí forest before dropping to the border post.

No public bus runs all the way to the pass. Tours from San Martín take 5 to 6 hours round-trip and include stops at Yuco beach and Chachín waterfall. If you're driving yourself, fill up in town — there's no fuel after the turnoff.

Immigration and the Ferry to Chile

The Argentine border post at Hua Hum is a small, quiet facility. Morning is the time to cross; the post closes at 13:00, and if you miss that window you're spending another night in Argentina. Both sides require a passport stamp, and Chilean officials collect the Mercosur form. The ferry across Lago Pirehueico runs on a schedule, not continuously — five to six departures daily in summer between 8:00 and 19:00, fewer in winter. The last boat leaves around 18:30. Tickets cost roughly 25,000 Argentine pesos for a vehicle and passengers, payable on the spot by cash or card. Book ahead in January and February; the boat fills.

The Mossy Forest Trail and Nonthué Lookout

A 3-Kilometer Walk Through Valdivian Rainforest

The trail starts at the Argentine border post and runs 3 kilometers one-way to a mirador over Lago Nonthué. The first kilometer follows the Hua Hum River, where spray keeps the araucaria roots and fallen logs slick with moss. Sphagnum covers the seep areas, and the air smells of wet bark and myrtle. I walked it at 8 a.m. in December and had fog until 9:30 — the mist hangs in the trees and muffles everything. Wear shoes with grip; the log bridges are damp year-round.

This is Mapuche land, co-managed with the national park. The Curruhuinca community owns the section the trail crosses. Ask before photographing people or their homes.

What the Trail Costs (and What It Doesn't)

Entering Lanín National Park through the Hua Hum booth is free. The main park entrance charges 3,000 Argentine pesos, but this secondary access uses an honor-sign system — no card, no turnstile. Dogs and drones are banned. Stay on the marked path and follow the stream; off-trail walking damages the moss beds, which take decades to recover.

Combining the Trail with Chachín Waterfall and Yuco

Most day tours pair the Hua Hum trail with Cascada Chachín, a 30-meter fall reached by a 30-minute walk through Valdivian rainforest, and the volcanic-sand coves at Península de Yuco. The full circuit takes 6 hours from San Martín. If you're on your own, do Chachín first — the light is better before noon — then drive to the border for the forest walk. Hostería Hua Hum, near the dock, is the only place for a sit-down snack; it also has views over Lago Nonthué.

Rafting the Hua Hum River

The Hua Hum River runs cold and fast between rock walls, fed by snowmelt from the surrounding peaks. Rafting operators in San Martín offer half-day trips on Class II and III rapids, suitable for beginners but not boring for people who've paddled before. Trips include shuttle from town and all gear. The season runs from November through March; water levels drop in late summer, making the rapids tamer but the scenery just as good. Book at least a day ahead in peak season.

Frequently Asked Questions

Do I need a reservation to hike the Hua Hum trail?

No. The trail is free and open without booking. You sign in at the self-service booth at the border post. The only reservation you might need is for the Pirehueico ferry if you're continuing to Chile — book that at least a day ahead in summer.

Can I cross to Chile and come back the same day?

Not realistically. The ferry takes 1.5 hours each way, plus immigration formalities on both sides, and the last return boat leaves Chile around 18:30. You'd have no time on the Chilean side. Plan an overnight in Panguipulli or Puerto Fuy instead.

What's the best month to visit Hua Hum?

December through March offers the most reliable weather — temperatures between 10°C and 22°C, longer daylight, and the ferry running its full summer schedule. The moss forest is at its greenest in November and December, when spring runoff keeps everything damp. Winter visits are possible because the pass stays open, but expect rain and fewer ferry departures.

Is the road to Hua Hum suitable for a rental car?

Yes, in dry conditions. The gravel section is graded and passable for standard sedans. After heavy rain, washouts can appear — check with your rental company or the tourist office in San Martín before heading out. No 4x4 needed.

Are there facilities at the border post?

Very limited. There are restrooms at the Argentine immigration building and a small kiosk selling drinks and snacks during high season. Bring water and food from San Martín. Fuel, ATMs, and medical services are all in town, 47 kilometers away.