My husband and I just completed this crossing from Bariloche to Puerto Varas (you can also go to Puerto Montt and do the trip in the other direction). I thought I would share my experience as I found it difficult to get a good idea about the trip before booking. First of all it is quite expensive - about USD $ 240 per person. The group of people doing the crossing have a guide with them - there were about 60 people doing the crossing and this seems to be the maximum that can be accommodated due to the size of the second ferry.
Here are a few facts which we were unaware of:-
1. The tour company picks you up at your Bariloche hotel by bus - they told us this would be at 8:45AM but the bus did not arrive until about 10:00AM. It did not seem to be running late or anything - the company (Turisur) just did not estimate the correct time. We were the last people to be picked up and the bus (large tourist coach) was totally packed - we got the last 2 seats.
2. Your luggage is checked through to your final destination (either Puerto Varas or Puerto Montt).
3. The first of 3 ferries leave from the small port near the Hotel Llao Llao so it takes at least 30 minutes to get there from Bariloche.
4. When we arrived at the port we had to pay a port tax of $9 (pesos) per person - not much but a bit of a hassle as you had to line up at the counter to pay this - then you had to temporarily claim your luggage as it was put through an xray scanner (for reasons which were unclear).
5. The first ferry was already full of day trippers and there were almost no seats - certainly all good seats were taken and people were really squashed in. Quite a surprise as we were expecting a private ferry for people doing the full crossing - this is not the case. This ferry left sometime around 10:45am and took about 1 hour 30 minutes. Fortunately it was a beautiful clear day; however, it was somewhat difficult to really enjoy the view and take photos as the ferry was so crowded,
6. On dis-embarcation of the first ferry - people doing the Lakes Crossing (about 60) were taken by bus to the next ferry - a short trip of about 15 minutes - it in fact took much longer as they wait around so people can take photos and the luggage needs to be offloaded etc.
7. The second ferry was quite small - only people doing the crossing took this one - the ride was only 30 minutes and the views were outstanding.
8. On dis-embarking the second ferry you pass through Argentinian exit procedures - passport stamp and possible luggage search. This took some 45 minutes for all 60 passengers. You can also change money here and there is a small snack bar (as we found out later it is probably a good idea to buy a drink and snack at the point - we did not). There are also toilet facilities. All quite amazing as you are literally in the middle of nowhere.
9. From here you take a bus (there were 2 busses due to the number of people) to Puella in Chile. There is a changing of the guard from your Argintinian to your Chilean guide. We felt the Chilean guide was more helpful, friendly and informative.
10. This bus ride takes 1 hour and 30 minutes and goes over the mountains on a steep windy gravel road - so its very slow - you only go about 30k's.
11. At Peulla you must first go through Chilean immigration and customs - a process which took about 45 minutes. We had been warned (by our Argintinian guide) that the Chilean customs were 'ruthless' - searching all bags and 'just looking for a reason' to fine you US$200 for some minor infringement (you are not allowed to bring in any fresh food etc). This was not the case at all - the immigration and customs officials were extremely friendly.
12. At Puella there is a hotel on the edge of the lake where people doing the 2 day trip stay overnight and the people on the one day crossing can have lunch (at their own expense). However at this stage it was already 3:30pm and the bus to the third and final ferry left the hotel at 4:00pm (you could also walk the 800m to the ferry if your wished). We felt there was insufficient time to have lunch so we decided to just have a drink but we could not get served - hence my comment about buying a drink / snack at the previous stop.
13. Since we now knew that this third ferry was also a public ferry and would probably also be packed out - we choose to walk to the ferry and get there early (ie before its 4:30pm departure) so we could secure a seat. As it was - this ferry was also totally packed with day-trippers and school students on a day excursion). Fortunately the ferry had a snack bar so we could get some drinks and a bag of chips.
13. This ferry was scheduled to take 1 hour 45 minutes but for some reason it took much longer - we finally arrived at about 6:45pm. The views of the volcanos were great even though it had clouded over a bit.
14. On arrival there were a couple of tourist coaches which took you to Puerto Varas or Puerto Montt - they dropped passengers off at some of the hotels but not all. We were dropped in the middle of town - fortunately our hotel (Hotel Arrebol) figured this all out and were there to meet us. We finally got to our hotel 8:30pm.
All in all - I found the trip to be a bit tedious with the packed ferries and the waiting around and bus transfers. Fortunately it was a great day so the scenery was excellent. I'm just posting this so that people can get a better idea what the trip is like as the information on the web is quite vague. I think it's one of those experiences where the memories of the tedious aspects will fade and it will seem like a great experience - and will make a good travel tale.