The fire is understood to have started in one of the boats that was fastened to the dock and quickly spread through to the other two.
Explosions were heard throughout the vicinity and all three boats were reportedly complete destroyed by the blaze, which broke out late Tuesday night.
Lisbon Port Commander Malaquias Domingues told the media that a fourth boat was also damaged by the flames but was still afloat when fire and police services arrived at the scene.
“We have three leisure boats, like yachts, which were practically entirely consumed by the fire and sank. Then there was a fourth boat that despite still being afloat shows signs of significant damage”, the commander explained.
The fire was extinguished at around 1.45am Wednesday morning and did not cause any victims.
Maritime and PJ police launched investigations to determine how the fire started and suspect a man intentionally started the fire. Newspaper Correio da Manhã reports authorities suspect a 26-year-old man from Zambujal, Amadora, started the fire on his father’s €80,000 boat as revenge following a family feud.