Open water swimming (OWS) in China is closely tied to triathlon’s spread. Between 2012-2016, domestic triathlon events grew from a handful to hundreds; pandemic-era outdoor demand growth made OWS acceptable to many non-triathlon enthusiasts as a standalone activity.
## Key Differences: Pool to Open Water
**Sighting**: open water has no lane lines — periodic head-up observation to locate targets (buoys, bridges, shoreline markers) is required. Sighting frequency: beginners every 4-6 strokes; experienced swimmers every 8-12. Sighting too frequently causes legs to drop, increasing drag.
**Currents and swells**: ocean tidal currents and swells significantly affect swimming trajectory and efficiency. Beginner recommendation: start with calm lakes to practice open water technique before entering ocean or river environments. Understanding local hydrological conditions (tide times, current direction) is fundamental to ocean swimming safety.
**Wetsuit**: full or short-leg neoprene suits provide buoyancy assistance (can improve speed by 3-8 seconds per 100m) and thermal protection (essential when water temperature is below 18°C). Key purchase parameters: thickness (1.5mm-5mm; thicker = warmer but less flexible); fit (armpits/shoulders must not be too tight or they’ll restrict the stroke).
## Safety Standards
Open water swimming is a high drowning-risk environment: no lane rope protection, low visibility, and potentially extreme cold water temperatures causing cold shock. Basic safety rules: never swim alone; carry a swim buoy/tow float (provides emergency buoyancy and increases visibility); inform others of your plan (departure location/expected return time); assess water temperature and physical condition before entry. In triathlon events, many DNF swimming incidents occur at race start with cold water and mass simultaneous entry. If panic sets in, immediately roll to supine floating position — the most important self-rescue technique.
See [Ultramarathon Sports Science](https://sunqi.org/ultramarathon-science-en/) and [World Aquatics Open Water rules](https://www.worldaquatics.com/open-water/).
