- Because there are so many different types of annelidas there is a great range of different areas that one might live in.
- Earthworms are found in many terrestrial environments ranging from semiarid habitats to moist, well-vegetated areas.
- Earthworms are more common in wetter areas and can be found in soil, leaf litter and under rocks and logs.
- Many are often found on the surface after heavy rain, moving out of the soil as it becomes waterlogged.
- Most leeches are freshwater animals, but many terrestrial and marine species occur.
- Land leeches are common on the ground or in low foliage in wet rain forests. In drier forests they may be found on the ground in seepage moistened places. Most do not enter water and cannot swim, but can survive periods of immersion.
- Some are also marine worms and live under water.