This dive site is the wreckage of the tugboat 'Marialva', located off the mouth of the Douro River in Portugal. Resting on a sandy bottom at a maximum depth of 24 meters, the wreck is described as very damaged and silted, requiring good buoyancy control from divers. Its history as a tugboat offers a glimpse into maritime operations, now serving as an artificial reef.
The Marialva wreck attracts a variety of marine life. Divers can regularly observe pouts, conger eels, octopuses, and tub gurnard taking refuge in and around the structure. Occasionally, schools of blue whiting pass by, and larger species such as rays and small-spotted catshark can also be encountered.
As an accessible-only-by-boat site, planning is essential. The silted nature means visibility can be a factor, so checking local conditions is advisable. While suitable for experienced freedivers due to its depth, its wreck characteristics make it primarily a scuba destination. There is no specific best time mentioned, but generally calmer, warmer months are preferred for coastal diving.
