The distance between Chile's Puerto Natales—the gateway to Torres del Paine National Park—and El Chaltén in Argentina is 260 miles (420 km). Although the two destinations are close, they are separated by a border, so this necessitates some extra planning. The best option is renting a car, which will take about 6 hours. If you don't mind an extra hour of travel time, you can also take a bus. Keep in mind that you will have to transfer buses in El Calafate since there are no direct buses from Puerto Natales.
When you're done exploring El Chaltén and its surroundings, you might want to visit some of Argentina's hidden gems. If you're interested in seeing some of the best lakes and parks in El Chalten and the Argentinian Patagonia, consider this 6-day itinerary.
By Rental Car
Duration: 6 hours, plus border control
Renting a car is the best options for traveling between Puerto Natales and El Chaltén, but make sure your rental company will allow you to cross the border into Argentina, and make sure you get them to provide the appropriate documents for you to show to the border agents
Three hours into your drive on RN40, you'll arrive in Torres del Paine. You can stop here for a few hours, or stay overnight and add a visit to the Torres del Paine National Park before continuing further. When you're ready to continue on RN40, you have another three hours before you'll have the option to make a detour on Route 11 to stop in El Calafate and visit the famous Perito Moreno Glacier in Los Glaciares National Park. The best thing is to spend at least one day here to get the most out of your visit.
One hour past El Calafate, you'll get to La Leona—a great place to stop for kayaking, hiking in the petrified forest, and relaxing for a few hours. About two hours further along, you'll arrive in El Chaltén and see Mount Fitz Roy waiting for you. Bear in mind that you can't leave your rental car in Argentina, so only choose this option if you'll be traveling back to Chile.
Duration: 9 hours
Buses leave from Puerto Natale's main bus terminal many times each day, and it will take approximately nine hours to reach El Chaltén. The first half of the journey takes about five hours and buses usually run two or three times per day, but remember that you'll have to make a transfer in El Calafate. Consider taking an early bus so that you can stop and hike in El Calafate, stay overnight, and then hop on the early bus the next day. From El Calafate, the rest of the journey to El Chaltén takes about three hours.