This is a road trip, so you need a car; the loop runs north from Glasgow up to Inverness, so a one-way hire dropped in Inverness saves a long backtrack. If you are already in the UK, driving or the train to Glasgow works just as well. One thing to fix in your head before day one: this itinerary assumes late spring to early autumn, roughly May to September, when the water is at its least punishing. Even so, Scottish lochs rarely climb above 15C and many sit around 12C all summer, so every swim here is a cold-water swim. Glasgow Airport to the loch is about 40 minutes. Book flights →

Base yourself around Balmaha or Drymen on the quieter eastern shore, inside Loch Lomond and the Trossachs National Park and close to the best swim spots. Drop the bags, sort out swim kit for later, and take it slowly on the first afternoon. Search hotels →

Milarrochy Bay, a couple of kilometres past Balmaha, is the gentlest possible introduction: a shallow, sandy bay with easy shore entry and views across to the wooded islands. Treat this as an acclimatisation swim rather than a distance one. Never swim alone, get in slowly to let your body adjust to the cold rather than diving straight in, and stay close to shore, as it can shelve off quickly and get choppy in a wind. Wear a bright cap and, ideally, tow a brightly coloured float so paddlers and boats can see you. Know where you are getting out before you get in, keep it short, and have warm dry layers and a hot drink ready for straight afterwards.

The Oak Tree Inn is the hub of Balmaha, a walkers' and swimmers' pub serving generous Scottish plates and its own ales. It is an easy, unhurried first night with everything you have earned after a cold dip; book ahead in high summer as it fills up with West Highland Way walkers.