Sesimbra Diving: Portugal's Biggest Cluster of Dive Licences
by Yannick Schroth
Aug 27, 2026
6 min read
Photo: Diego Delso, Wikimedia Commons, CC BY-SA 4.0.
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Reefs, rules and operators all change. Confirm the current picture before you book.
Key takeaways
- First in the country for diving. 18 of Portugal's 253 diving licences are in this one concelho, counted from the whole register on 27 August 2026.
- Three designations, not one. Arrábida is a Nature Park designated 1976, a Habitats Directive site since 2008 and an OSPAR Marine Protected Area since 2015.
- All 30 hold an RNAAT licence, which is every business on this page.
- It is not only a dive town. The schools here also list freediving and surfing, and the licence does not distinguish: diving is one item, board sports another.
The number that makes this town unusual
Diving licences are scarce in Portugal. The RNAAT register carries 253 of them against 1,300 for board sports, and they cluster hard: Sesimbra 18, Lagos and Setúbal 13 each, Lisbon 11. Sesimbra is a town of a few thousand people and it holds seven per cent of the country's dive licences.
What makes that legible is the coast. Sesimbra sits under the Arrábida ridge on a south-facing bay, which is shelter on a coast that mostly does not have any, and shelter is what diving needs. The same geography that makes the north Atlantic beaches good for surf makes them poor for diving, and the trade runs the other way here.
Three designations over the same water
The World Database on Protected Areas carries Arrábida three times, and they are different instruments rather than repetitions of one. Arrábida Nature Park, IUCN management category V, designated 1976, national. Arrábida / Espichel, a Site of Community Importance under the EU Habitats Directive, designated 2008. And Arrábida as an OSPAR Marine Protected Area, designated 2015, under collaborative governance.
Three layers is not three times the protection; it is three bodies with three sets of rules over one piece of sea. What any of them permits on a given day — where you may anchor, what you may touch, which zones are closed — is not something we can tell you. Portugal's ICNF publishes the management plan and its pages returned no readable text for us, so we cite the designations and stop there. Your dive centre will know.
None of the three says anything about a business. No school on this page is certified or endorsed by any of them.
What the 30 schools say about themselves
Reading the school websites we hold turns up PADI on 3, SSI on 1 and AIDA on 1.
That comes from reading 18 sites, 54 pages in all. 12 more did not answer at all. The operator list for Sesimbra gives the page each name was read on. Absence from the count means we did not find it on the pages we opened, which is not the same as not being held.
Not one of the 30 publishes the languages their instructors teach in. For a town whose customers arrive from Lisbon and from abroad in roughly equal measure, that is worth asking about before you book rather than after.
The rest of the Portuguese coast is on the same footing: our Peniche and Ericeira guides, the comparison between them, and what an RNAAT licence proves, which carries the national ranking this page draws on.
What we could not confirm
What the marine protected area actually requires. Three designations exist and we have their dates, categories and governing types from the WDPA. The rules themselves live with ICNF and we could not read them.
Which of these businesses actually dive the park. A diving licence in the concelho of Sesimbra is not a statement about where the boat goes.
Prices and quality. Neither verified, and nobody has assessed these schools.
Questions
Why does Sesimbra have so many dive centres?
It holds 18 of Portugal's 253 state diving licences, more than any other concelho, counted from the whole RNAAT register on 27 August 2026. The town sits on a south-facing bay under the Arrábida ridge, which is shelter on a coast that mostly lacks it.
Is diving in Sesimbra inside a marine protected area?
The water beside the town carries three designations recorded in the World Database on Protected Areas: Arrábida Nature Park from 1976, a Habitats Directive site from 2008 and an OSPAR Marine Protected Area from 2015. What each permits is set by the managing authority, whose own pages we could not read, so ask your dive centre.
Does the licence say a dive centre is any good?
No. It says the state permits the business to sell diving. It carries no assessment of instructors, equipment or safety, and no register or inspector has judged the schools on this page in any source we could read.
Writes NOMADREEF and compiles its operator directory. This guide is desk research, not a trip report, and says so at the top. About the author
Sources
- Turismo de Portugal, Dados Abertos, the RNAAT register: 13,152 establishments, 1,300 licensed for board sports, 253 for diving, with the per-concelho breakdown. Read 2026-08-27.
- IUCN and UNEP-WCMC, World Database on Protected Areas, record 1340. Arrábida: Nature Park, IUCN category V, designated 1976. Records 555531080 (Habitats Directive, 2008) and 555599537 (OSPAR Marine Protected Area, 2015) cover the same coast. Portugal's own ICNF pages returned no readable text, so the designation is cited from the WDPA. Read 2026-08-27.
- Each school's own website, opened on 2026-08-26. Every agency name on the operator list is published beside the sentence it was read from. No aggregator, booking portal or review was used.