There is so little development in this part of the world that one of the only ways to see the stunning Patagonian Fjords is through the industrial-style Navimag Ferry that makes its 3 night / 4 day route between Puerto Natales and Puerto Montt from October to March.
I personally enjoyed the experience of the journey in such an isolated part of the world, watching the albatross and whales popping along to say hello, and being in amongst the interesting people you get chatting to onboard, so I’m glad I did it.
But there are a few things to be aware of:
1. It is heavily weather dependant (we were not very lucky).
2. The ferry is not a cruise ship so is far from luxury (think less Royal Caribbean and more Dover-Calais).
3. You are stuck on the ferry for minimum 3 full days with no stops, no wifi and no alcohol.
4. You must give yourself at least 24 hours leeway in timings as it seems to always run late and bear in mind the ferry usually only leaves once a week.
5. Driving The Carretera Austral looks to be a very good alternative.