The archipelagos of the National Park can only be accessed from the sea, by means of maritime transportation services for passengers which operate on designated dates or, with pre-authorization, by private boat. Nowadays, various shipping vessels offer regular service during Easter Week, weekends in May and during the summer for visitation to the islands of Cíes and Ons.

The following is a list of nautical transportation services that the vessels are authorized to carry out:

Boats to Illas Cíes:

Company: Naviera Mar de Ons, S.l.
Tel: 986 22 52 72
Boarding Locations: Vigo, Baiona, Cangas de Morrazo.
Time Period: Easter Week, weekends in May, summer.
Web Page: Naviera Mar de Ons.

Boats to the Illa de Ons:

Company: Cruceros Illas de Ons.
Tel: 627 90 00 17
Boarding Location: Bueu.
Time Period: Easter Week, weekends in May, summer.
Web Page: Cruceros Illas de Ons.

Company: Cruceros Rías Baixas
Tel: 986 73 13 43
Boarding Locations: Marín, Sanxenxo, and Portonovo.
Time Period: Easter Week, weekends in May, summer.
Web Page: Cruceros Rias Baixas

Company: Naviera Illa de Ons.
Tel: 986 32 00 48
Boarding Location: Bueu.
Time Period: Easter Week, weekends in May, summer.
Web Page: Naviera Illa de Ons.

Company: Naviera Mar de Ons.
Tel: 986 22 52 72
Boarding Locations: Marín, Sanxenxo, and Portonovo.
Time Period: Easter Week, weekends in May, summer.
Web Page: Naviera Mar de Ons.