| Synonym | Author | CoL Status | Valid | Synonymy | Combination |
|---|---|---|---|---|---|
| Sipunculus aequabilis | Sluiter, 1902 | synonym | No | junior synonym |
original combination |
| Sipunculus infrons | Sluiter, 1902 | synonym | No | junior synonym |
original combination |
| Sipunculus nitidus | Sluiter, 1900 | synonym | No | junior synonym |
original combination |
| Sipunculus norvegicus | Danielssen, 1869 | accepted name | Yes | senior synonym |
original combination |
| Sipunculus priapuloides | Koren & Danielssen, 1877 | synonym | No | junior synonym |
original combination |
| Sipunculus priapuloides var. americana | Gerould, 1913 | synonym | No | junior synonym |
original combination |