Blue Swimmer Crab

Scientific name: Portunus armatus
  • Updated
    30/06/26
  • Read time
    2 minutes
Portunus pelagius Click to enlarge image
Blue Swimmer Crab (Portunus pelagius) is a large crab named for its distinctive colour and large front pincers. Image: Brooke Carson-Ewart
© Australian Museum

Fast Facts

  • Classification
    Genus
    Portunus
    Species
    armatus
    Family
    Portunidae
    Infraorder
    Brachyura
    Order
    Decapoda
    Class
    Malacostraca
    Subphylum
    Crustacea
    Phylum
    Arthropoda
    Kingdom
    Animalia
  • Size Range
    19 cm

The Blue Swimmer Crab is named for its distinctive colour.

The Blue Swimmer Crab has white spots and long pincers.
The male Blue Swimmer Crab (Portunus pelagicus) is blue in colour with white spots and with long chelipeds (pincers). Image: Dr Isobel Bennett
© Australian Museum

Identification

The Blue Swimmer Crab is easily recognised by its distinctive shape and blue colour, and its large front pincers.

The males are bright blue with white spots and long chelipeds (pincers). The carapace can be up to 20 centimetres wide.

Female Blue Swimmer Crabs are known as 'jennies' and are less colourful than the males. They are a duller green/brown, with a more rounded carapace.

Habitat

This map shows species occurrence observations from data recorded in the Atlas of Living Australia.

Generally, the Blue Swimmer Crab occurs in the deeper waters of intertidal estuaries but occasionally it enters shallower waters.

Distribution

The Blue Swimmer Crab is found from Northern Queensland to Eden in New South Wales; Western Australia and the South Australian gulfs; also New Zealand and New Caledonia.

Seasonality

The Blue Swimmer Crab is a popular food in Australia and is targeted and caught in large numbers by professional and recreational fishers. These crabs enter estuaries as juveniles and grow quite quickly, maturing after one year.