The ‘Half Channel’ option
33.3/2 BUILD
For those looking to challenge themselves at different levels, we have a smaller but nonetheless rewarding challenge, but with no single swim greater than 5km
“We always try to encourage swimmers to take on the full 33.3km challenge because time and again, we’ve seen that most competent swimmers can push beyond their perceived physical and mental limits, also carried by the incredible energy of the 33.3 tribe, and nail the full 33.3. However, we also recognise that some swimmers prefer to set themselves a slightly less demanding goal - while still achieving an impressive swim. That’s why we created the 33.3/2 BUILD option: to offer a stepping stone within the UltraSwim experience.” — Mark Turner, Founder, UltraSwim 33.3
33.3/2 BUILD Option – Step Up Your Endurance
Perfect for swimmers who want to build toward longer distances, the 33.3/2 BUILD option covers 3-5km per day over four days. You’ll experience key highlights of the full challenge, including:
✔️ The longest swim on Day 3, alongside the full-distance swimmers, where you'll push past previous limits.
✔️ This is NOT a competitive race format - no rankings or podiums - but you’ll still be a proud ‘half Channel’ Finisher if you make all the swims inside the 2km/h cutoff
✔️ Experience tells us you’ll be back the following year to take on the full 33.3 CLASSIC!
What does a 33.3/2 BUILD day look like?
There is no difference in the experience, information provided or price for 33.3/2 BUILD compared with the full 33.3 - but the swims you will take on are of course shorter each day, and are part or all of the full course depending on logistical or weather constraints. You'll sometimes start with the 33.3ers and other times finish with them.
See below an example of the planned swims in #7Croatia in 2025 [NB until #10 this format was known as 11.1 and 22.2 - these have been combined in to one shorter format for 2026]
✨ “The first 22.2 I swam was magic as it made me (and Marie) feel that it was doable!” – Karen Heng, UK ✨ Karen then went on to complete very well her first full 33.3 at #5Montenegro 2024.
