Swimming across a fast-moving river without a flotation device is a very challenging task, so be sure to proceed with caution. Here are some tips: 1. **Know the river**: Observe the river's speed, turbulence, and depth before attempting to swim across. Choose an area with slow currents. 2. **Choose the right route**: Look for shallow areas leading into the river, and try to avoid the strongest currents. Look for natural turns or areas with calmer currents. 3. **Stay calm**: Once in the water, stay calm and avoid panicking. Nervousness drains energy and increases the risk of losing control. 4. **Use the right stroke**: Use a smooth, efficient stroke, such as freestyle or breaststroke, to reduce energy consumption and improve propulsion efficiency. 5. **Stay level**: Avoid swimming upright and keep your body level to help reduce water resistance. 6. **Pay attention to the current**: Use the power of the current and swim with the direction of the current, rather than forcing your way upstream. 7. **Use support**: If possible, swim as close to the riverbank as possible to use the support of the riverbank and reduce the impact of the water flow on your body. 8. **Seek help**: If possible, seek help from others or use tools such as ropes to assist in crossing the river. 9. **Protect yourself**: If the water flow is very strong, it is recommended not to try alone, find a professional or team to do it together. 10. **Safety first**: If the conditions are very dangerous, it is best not to try to swim across the river, and you can find other safe ways to cross the river. Please pay attention to safety, evaluate your own swimming ability and the danger of the river, and seek professional advice and help when necessary.