These I've already done:
- Swim 1500 meters in one session.
- Swim while it's sunny.
- Swim in a 25 meter pool.
I still have to go for these:
- Have a streak of swimming weeks for 1 month.
- Have a streak of swimming weeks for 2 months.
- Have a streak of swimming weeks for 3 months.
- Have a streak of swimming weeks for 4 months.
- Have a streak of swimming weeks for 5 months.
- Have a streak of swimming weeks for 6 months.
- Swim 2000 meters in one session.
- Swim 2500 meters in one session.
- Swim 3000 meters in one session.
- Swim 3500 meters in one session.
- Swim 4000 meters in one session.
- Swim while it's raining.
- Swim while it's snowing.
- Swim when the sun is just rising.
- Swim when the sun is just setting.
- Swim when it's dark.
- Swim 2 times a week.
- Swim 3 times a week.
- Swim 4 times a week.
- Swim 5 times a week.
- Swim 6 times a week.
- Swim on every day of a week.
- Swim in a sea.
- Swim in an ocean.
- Swim in a lake.
- Swim in a river.
- Swim in a 33 meter pool.
- Swim in a 50 meter pool.
- Swim in 5 cities.
- Swim in 10 cities.
- Swim in 15 cities.
- Swim in 20 cities.
- Swim in 25 cities.
- Swim in 30 cities.
- Swim in 5 open waters.
- Swim in 10 open waters.
- Swim in 15 open waters.
- Swim in 20 open waters.
- Swim in 25 open waters.
- Swim in 30 open waters.
- Swim in Africa.
- Swim in Asia.
- Swim in Australia.
- Swim in North America.
- Swim in South America.
This list is a constant work in progress, just like fighting through it.