The route is walkable, by following The Thames Path. It is also possible to cycle the route, although there are a large number of kissing style gates where you may have to lift your bikes to get through and it may be difficult with tag-alongs.
Please note that there is still a diversion in place on the Thames Path, due to the footbridge at Temple Lock being closed. More details…
Supporters that start with their swimmer at Higginson Park can walk upstream as far as Temple Lock, and then walk back downstream alongside their swimmer. Alternatively they can stay at the event village or go into Marlow for a coffee, and wait for the swimmers to return.
Supporters can be dropped at the start of the full-distance in Henley by friends or family with their swimmer, and walk the full distance of the course. There is public parking available in Henley Town Centre near to the start of the swim, but spectators and swimmers would have to make their own way back to their cars after the swim.