Dolphins off the coast of Lisbon
This guide was led by our team of marine biologists. If you’d like to see these species in the wild, check out our Ethical & Licensed Dolphin Watching in Lisbon.
Over the years, dolphin sightings off the coast of Lisbon have increased exponentially. In fact, there has been a greater effort, with more boats and companies in the area contributing to their observation, further piquing public interest and allowing us to obtain more detailed data on the presence of these animals and their use of territory.
The existence of the Tagus River, which bathes part of the Lisbon area, enriches the surrounding areas through the flow of water and nutrients, contributing to a richer ecosystem, attracting numerous species, and contributing to the great biodiversity of the Lisbon Coast (fish, mollusks, crustaceans, invertebrates, reptiles, amphibians, marine mammals, birds).
Dolphins find food availability, refuge, and biological benefits on our coast. In this area, these animals are top predators and good indicators of environmental quality.
Therefore, despite the anthropogenic threats they may face, dolphins find suitable conditions in these waters to feed and reproduce, and their observation is common, thus guaranteeing that we can affirm that there are resident species.
Quick Facts
Number of species recorded
8 species were recorded on our dolphin watching boat tours.
Most common species
Common Dolphin, Bottlenose Dolphin, Harbour Porpoise and Striped Dolphin
Best time of year for observation
We can observe dolphins throughout the year.
Where they are most frequent
Most dolphin sightings occur at sea, but also in the Tagus estuary (mainly during the summer).
Species Gallery
Common Dolphin
Scientific name: Delphinus delphis
Conservation status: Least Concern (IUCN)
Probability of sighting: High
When we see it: All year
ID notes: Distinct yellow‑tan hourglass flank pattern; dark cape with “V” under fin; prominent fin and beak; slender body; active, often aerial.
Why Lisbon?: Upwelling and river‑plume productivity concentrate prey near shore.
Did you know? Group size can exceed 100 animals during feeding events.
Striped Dolphin
Scientific name: Stenella coeruleoalba
Conservation status: Least Concern (IUCN)
Probability of sighting: Medium
When we see it: Spring–autumn, occasional winter.
ID notes: Dark shoulder stripes from eye to flipper; clean, high‑speed leaps; prominent fin; usually in large number; active at surface.
Why Lisbon?: Productive shelf waters during upwelling seasons.
Did you know? Their leaps can include lateral spins when surfing swells.
Bottlenose Dolphin
Scientific name: Tursiops truncatus
Conservation status: Least Concern (IUCN)
Probability of sighting: High
When we see it: Year‑round but irregular; often in small groups.
ID notes: Robust head and body, distinct beak with melon crease, tall falcate dorsal fin; uniform grey.
Why Lisbon?: Variety of prey along the coast and shelter in calm conditions.
Did you know? Individuals can be photo‑identified by nicks on the dorsal fin.
Risso’s Dolphin
Scientific name: Grampus griseus
Conservation status: Least Concern (IUCN)
Probability of sighting: Occasional
When we see it: Mostly late spring–autumn in deeper nearshore waters.
ID notes: Large blunt head with no distinct beak; tall, curved dorsal fin; adults often appear pale or whitish due to extensive scarring from social interactions and squid.
Why Lisbon?: Access to productive shelf‑edge waters and squid associated with upwelling.
Did you know? Individuals can be recognised by their unique scar patterns, which increase with age.
Killer Whale
Scientific name: Orcinus orca
Conservation status: Data Deficient (IUCN; status varies by population)
Probability of sighting: Occasional
When we see it: More likely late spring - autumn following migratory prey.
ID notes: Bold black‑and‑white pattern; tall triangular dorsal fin (up to 1.8 m in adult males); prominent white eye‑patch.
Why Lisbon?: Coastal migration routes occasionally pass our area when prey is abundant.
Did you know? Orcas have distinct dialects and cultures - learned behaviours passed within family groups.
Short‑finned Pilot Whale
Scientific name: Globicephala macrorhynchus
Conservation status: Least Concern (IUNC)
Probability of sighting: Rare to occasional
When we see it: More likely during warmer water incursions.
ID notes: Very similar to long‑finned; pectoral fins proportionally shorter; at sea, separation is difficult - range and conditions help.
Why Lisbon?: Transitional zone between temperate and subtropical influences allows sporadic appearances.
Did you know? Their social structure is matrilineal, with strong family bonds.
Long‑finned Pilot Whale
Scientific name: Globicephala melas
Conservation status: Least Concern (IUNC)
Probability of sighting: Occasional
When we see it: More likely in cooler seasons/years.
ID notes: Large bulbous head with no distinct beak; very long, sickle‑shaped pectoral fins; tall, falcate dorsal fin set forward.
Why Lisbon?: Influence of upwelling and migrating squid/fish along the shelf.
Did you know? Groups can include several generations led by adult females.
Harbour Porpoise
Scientific name: Phocoena phocoena
Conservation status: Least Concern (IUCN)
Probability of sighting: High
When we see it: More likely in calm seas.
ID notes: Small size; triangular dorsal fin; low, rolling surfacing; no leaps.
Why Lisbon?: Edge of range; may use productive upwelling tongues.
Did you know? Their clicks are higher‑frequency than most dolphins.
Sightings
Biologists’ Notes:
During the high season (April–October) ocean conditions are generally more favourable for surveys, so we run more tours and conduct more at‑sea effort. As a result, raw sighting counts are higher in this period compared with the low season.
Since 2023 our fleet doubled, which produced a marked increase in the total number of sightings. Much of this rise is attributable to increased survey effort rather than a change in local populations.
Observation Success: Finding and observing marine mammals, especially at sea, can be a great challenge, and is strongly dependent on general weather and sea conditions. The best chances of finding cetaceans occur in calm seas, on windless and overcast days. Much is also dependent on the species involved (e.g., spending most of their time underwater), season, and even the time of the day, locality, and the type of boat used. However, a successful search is often also reliant on the crew, which has skills, practice, and motivation.
How We Identify Them
A single feature is rarely enough for a confident identification, so our golden rule is to collect information on as many characteristics as possible. We pay close attention to body size; dorsal fin position, shape, and colour; body and head shape, markings, and overall colouration; the blow; fluke shape and markings; surfacing behaviour and dive sequence; breaching and other activities; group size; and the main habitat. Here are some examples.
Science Deep‑Dive on the ecology of the group in the region of Lisbon
As top predators, the presence and distribution of dolphin species are strongly associated with the distribution of their prey. Globally, estuaries are recognized as sites of fish aggregation and abundance. Temperature, salinity, and dissolved oxygen will influence the spatial and seasonal distribution of their prey and may be the main reason we occasionally see dolphins in the river or nearby. The estuary provides spawning and nursery grounds for fish, attracting dolphins to forage. Because we frequently see nursery groups (mothers with calves) entering the river, we may think it is also a refuge area to protect and educate the younger ones in a small, rich feeding area.
Feeding and hunting strategies
Dolphins can use a wide variety of hunting techniques, which depend on the type of prey in sight and its location, and are associated with their size. Small dolphins will chase smaller prey because they swallow most prey whole, gripping it with their teeth and swallowing head-first. Dolphins primarily eat fish, cephalopods, and crustaceans. In our area, sardines are among the most preferred prey.
Dolphins are highly intelligent hunters, using cooperative strategies like herding fish into tight balls or onto shores (strand feeding) and employing unique tactics such as using mud nets or even sponges as tools to dislodge prey from the seafloor. Usually, they hunt as a group and combine methods with powerful sonar (echolocation) to find prey, often coordinating roles and even learning complex behaviors from mothers, demonstrating cultural transmission of hunting skills.
Predator–prey choreography
Seabirds are our spotters. When gannets wheel and shearwaters skim in tight loops, predators below are herding fish. Dolphins coordinate with rapid turns and bubble lines; whales may lunge through the school. Reading the “bird language” often leads us straight to cetaceans.
Effect on the food chain
Dolphins frequent the waters where the Tagus River meets the Atlantic Ocean, a rich area for fish, and are predators at the top. They are a key predator, leading to the control of the growth of smaller fish populations that could consume plankton and vegetation, contributing to the balance of the marine system.
Reproduction and life cycle
In general, dolphins don’t have a defined mating season. We can observe mating behaviours throughout the year, although they tend to become more frequent during summer, and dolphins are not monogamous. During mating, it’s common to see several males taking turns attempting to reproduce with a female.
The age of sexual maturity varies by species and sex, but broadly speaking, males reach sexual maturity between 8 and 14 years, while females usually mature a little earlier, between 5 and 13 years.
Average lifespan varies significantly by species, but in the wild it generally ranges from 20 to 40 years. Bottlenose dolphins often live longer, around 40–60 years (with females typically outliving males), and orcas can potentially live for over 90 years. Factors such as species, sex, environment, predators, pollution, and human impact all strongly influence how long an individual dolphin lives.
Behaviors that can be observed
We categorize dolphin behaviors into four main actions: Movement, Feeding, Resting, and Socialization. Within each action, there may be subcategories, depending on the observation. For example, socialization may include play behaviors among individuals within the same group, between species, or in relation to the vessel, mating behaviors, or demonstrations of social bonds.
The presence or absence of dolphin species, and their behavioral signals, indicate the environmental quality of the estuary, making them “flagship” species for conservation. This means Dolphins are good indicators of the quality of the environment.
Responsible Watching (Our Code)
At SeaEO-Tours, we proudly respect the code of conduct for cetacean watching. We do not impose our presence on our marine biologist-led tours.
1. Keep safe distances and approach parallel and slightly behind groups – never head‑on or cutting across travel paths.
2. Limit time with each group; move on if behaviour changes or calves are present.
3. Maintain steady speed; shift to neutral when animals approach the boat.
4. Avoid splitting groups, especially nursery groups; never feed, touch or swim with wildlife.
5. Reduce noise: no sudden accelerations; minimise engine and hull slaps.
6. Respect sensitive zones near bird roosts and estuary channels.
The protection of marine mammals in Portugal is governed by legislation that prohibits the capture, sale, and disturbance of these animals, notably Decree-Law No. 263/81 (general protection in the EEZ) and Decree-Law No. 9/2006 (rules for cetacean observation), which prohibit chasing, excessive noise, feeding, and touching, aiming at their conservation and the balance of the ecosystem, with specific rules applied in sensitive areas, in accordance with European directives.
Our Boat Tours
Our Boat Tours were carefully designed to offer the best nature and cultural experiences in the city.
Dolphin Watching Boat Tour
Birdwatching Boat Tour
Frequent Questions about Dolphins
What is the difference between a dolphin and a whale?
All dolphins are, in fact, whales. Scientifically, all whales, dolphins, and porpoises are classified as Cetacea. Within the Cetacea group, there are two subgroups: baleen whales and toothed whales. Dolphins are a type of toothed whale. Dolphins are simply smaller whales, with killer whales (orcas) being the largest type of dolphin. Baleen whales lack teeth and have two external blowholes, whereas toothed whales, the dolphin group, possess teeth, a single blowhole, and lack baleen.
Are dolphins afraid of sharks?
In general, dolphins avoid the presence of sharks, especially when they have calves in the group. However, sharks are generally solitary animals, while dolphins are social, which contributes to greater safety and defense. In case they must defend themselves against sharks, dolphins will force them to retreat. We have had sightings of groups of dolphins passing alongside sharks without any conflict or interest.
Are dolphins not afraid of boats?
It depends on the species, but in general, dolphins are not afraid of boats and often actively seek them out due to curiosity, playfulness, and to save energy by “bow-riding” to increase their swimming speed. However, excessive or non-compliant boat traffic can cause them stress and lead to negative responses.
Can we swim with dolphins in Portugal?
In mainland Portugal, swimming with wild dolphins is prohibited by law under Decree-Law No. 9/2006, which regulates the tourist observation of cetaceans and requires a distance and conduct that avoid disturbing the animals, with the Institute for Nature Conservation and Forests (ICNF) responsible for enforcement. Portugal’s islands, such as the Azores and Madeira, have specific rules allowing swimming under controlled, authorized conditions.
How do dolphins sleep?
Unlike humans, whales and dolphins are conscious breathers, meaning they must be awake to breathe. Whales and dolphins have at least one blowhole on the top of the head. Just like our nostrils. They breathe air through this blowhole at the surface and hold their breath while underwater. To ensure they don’t drown while sleeping, both whales and dolphins can shut down just one half of their brain when they’re asleep. The awake part of the brain ensures they rise to the surface to breathe when necessary. After a while, the sides of the brain swap roles, so both sides get a chance to rest.
If we could give it six stars we would!! Seven of us attended the 3hr dolphin tour with marine biologist excursion and had a great time. The two crew members were very knowledgeable about both the marine life and local history. We were fortunate to go on a very clear morning and saw LOTS of dolphins!! They were very respectful of the dolphins and kept our distance – sometimes the dolphins came right up to the boat out of curiosity anyway which was very cool!
Camille Keenan
October 2025, Google
Mini Glossary of Specific Terms
Marine Mammals
Most marine mammals, including dolphins and whales, belong to one of two major groups: Cetacea (cetaceans) and Pinnipedia (seals). The order Cetacea consists of three principal suborders, of which two have living representatives:
The Mysticeti are the baleen whales (four families: the right whales, Pygmy Right Whale, Grey Whale and the Rorquals) which lack teeth but possess two external blowholes.
The Odontoceti possess teeth, a single blowhole, and lack baleen, and are generally defined as the toothed whales and dolphins (the largest in terms of species being the oceanic dolphins and beaked whales, but also including the Sperm Whale, which forms its own family, the Beluga and Narwal, Porpoises, and several families of river dolphins).
Porpoises
Are a distinctive group of cetaceans, dolphin-like, small and beakless, with seven species belonging to three genera (Neophocaena, Phocoena, Phocoenoides). They are closely related to dolphins but have spatulate (not conical) teeth and several anatomical and structural characteristics. The Harbour porpoises are from the Phocoena genera.
Nursery groups
Are specialized, tight-knit pods of mother dolphins and their calves, sometimes with other females acting as “aunties,” formed for safety, shared care, and learning essential skills like hunting and socializing in a protected environment, often in shallower waters away from larger threats like predators and male dolphins
Echolocation
A system used by many cetaceans to orientate, navigate, and find food, sending out sounds and interpreting the returning echoes.
Bow-riding
Riding on the pressure wave in front of a ship or large whale.
IUCN Red List
The IUCN Red List is a critical indicator of the health of the world’s biodiversity. Far more than a list of species and their status, it is a powerful tool to inform and catalyse action for biodiversity conservation and policy change, critical to protecting the natural resources we need to survive. It provides information on range, population size, habitat and ecology, use and/or trade, threats, and conservation actions to inform necessary conservation decisions.
Scientific References
This guide is supported by scientific literature, field research, and the SeaEO team’s know-how. Below you can explore the main sources used.
Berta, A. (Ed). 2015. Whales, dolphins & porpoises: A natural history and species guide. University of Chicago Press
Carwardine, M. 1995. Whales, dolphins and porpoises: The clearest recognition guides available. Dorling Kindersley, London.
Kiszka, J., M. Woodstock, M. Heithaus. 2022. Functional Roles and Ecological Importance of Small Cetaceans in Aquatic Ecosystems. Frontiers, 9:803173: 1–7. Accessed on: January 13, 2026.
Latham, Katherine. “The scientists learning to speak whale” (online), BBC, 2024. Accessed on: January 14, 2026.
Monteiro, S.; Torres-Pereira, A.; Ferreira, M.; Vingada, J.V.; Nicolau, L.; Sequeira, M.; López, A.; Covelo, P.; Azevedo, M. I.; Hernandez-Milian, G.; Pierce, G. J.; Eira, C. 2025. “What’s on the menu? Diet of common minke whales (Balaenoptera acutorostrata) stranded on the Atlantic Iberian coast”. Marine Environmental Research, 205, 107024.
Shirihai, H., & Jarrett, B. 2006. Whales, dolphins and seals: A field guide to the marine mammals of the world. A. & C. Black, London.
Silva, M. 2022. “How do dolphins mate?” (online). Futurismo. Accessed on: January 13, 2026.
Silva, M. 1999. Diet of common dolphins, Delphinus delphis, off the Portuguese continental coast. J. Mar. Biol. Assoc. U. K., 79: 531–540.
Smith, C. 2023. “Delphinidae” (online), Animal Diversity Web. Accessed on: January 14, 2026.
Wells, R. S., & Scott, M. D. 1999. Bottlenose dolphin Tursiops truncatus (Montagu, 1821). Pages 137–182 in S. H. Ridgway & R. J. Harrison (eds.), Handbook of marine mammals: The second book of dolphins and porpoises. Academic Press, New York.