We weren't able to visit the fort since it is opened only from June to September but we did walk out to it during low tide. The low tide was at about 15:00 the day we visited but we were able to cross the beach from about 11:00 or 12:00, so as you have an idea how to plan your crossing time. It is amazing how I couldn't get any information on any website...The view was good and it was fun. But it is a shame with its short opening period because when we were there on early March, St Malo was already pretty much packed with tourists.
moretolearn
If you get a chance to walk out to Fort National when the tide is low, do it! There is something about walking out to the fort that is surreal when you've seen the view at high tide. The views back to St. Malo are worth the cost of admission. We did our own tour, with the English pamphlet provided, and that worked out pretty well, except that we weren't able to access all parts of the fort. They definitely give the tours priority. Just a note: the tours are free, but we saw the signs; they will ask for a tip.
360tolgau
Especially visit at night it impresses a lot when it is dark. But it is not so crowded at night so be careful.
mouseHerts
You get to the fort over the beach. Entrance is 5 euros which helps to pay for the restoration of the fort which was bombed in August 1944. I won't spoil the story of what happened, but it is a tragic one. If you are French, you get a guided tour which includes the ammunition store. If you are English you get a piece of paper which gives you a lot of information if you can follow it. The views from the fort are wonderful.
Aquilicus
The vast potential of this historical site is not realised. The 5 euro entrance fee for an adult is way too much for whats on offer. First you have to wait for the tides to be favourable to walk to the site. Although we went on 2 separate occasions and a guided tour is advertised, all we were given was a poorly worded description of the background to the site in English and had to find our own way. Views from the top are superb but apart from the underground ammunition store the site itself offers very little of interest. Careful not to purchase your ticket to close to the tide coming in or you may have to cut your visit short to get back, although , it is an all-day ticket so you can return and continue where you left off when the tide is out again.