| Onarheimsvatnet | |
| Other Name: | Opsangervatnet |
| Pushpin Map: | Vestland#Norway |
| Pushpin Label Position: | bottom |
| Pushpin Map Caption: | Location of the lake |
| Location: | Kvinnherad, Vestland |
| Coords: | 59.8541°N 5.7603°W |
| Basin Countries: | Norway |
| Area: | 2.25km2 |
| Reference: | NVE |
Onarheimsvatnet or Opsangervatnet is a lake in the municipality of Kvinnherad in Vestland county, Norway. The 2.25km2 lake is located between the villages of Husnes and Sunde.[1]