Nautilus Sub, also known as Nautilus, Escola do Mar, is a Portuguese diving and nautical school with more than 40 years of experience in recreational diving. Founded in the late 1980s, the company describes itself as a pioneer in bringing PADI training to Portugal and has trained students from beginner level through to instructor qualifications. Its focus is on consistent teaching, safety and enjoyable experiences on and around the water.

Nautilus Sub offers diving courses and certifications, introductory dives, snorkeling, guided diving outings, and events, expeditions and trips. Its services also include diving insurance, equipment maintenance and logistical support. For those interested in boating, the school provides recreational boating training and is accredited by DGRM to train recreational vessel operators.

The company operates a diving and nautical centre at Sesimbra’s Porto de Abrigo, with office and administrative locations in Corroios. Nautilus Sub welcomes newcomers and experienced participants alike, offering training and activities for people looking to build their skills, explore underwater environments or enjoy recreational nautical pursuits.