Historically, the islands have been a popular gateway for African migrants attempting to reach Europe.
Three African migrants travelled on a ship's rudder to reach Spain's Canary Islands, say authorities.
The men appeared to have symptoms of dehydration and hypothermia and were transferred to hospital for medical attention, said Salvamento Marítimo, Spain's maritime rescue service.
They had sat on the rudder of the Alithini II oil tanker, which left Lagos, Nigeria, on 17 November, and arrived in Las Palmas on Monday, according to the MarineTraffic website.
Las Palmas is the capital of Gran Canaria, one of Spain's Canary Islands situated off the northwest coast of Africa.
Historically, the islands have been a popular gateway for African migrants attempting to reach Europe since they are just 100 kilometres west of Morocco at their closest point to the African continent.
Spanish data shows migration by sea to the archipelago jumped 51% in the first five months of the year compared to 2021.
Though extremely dangerous, it is not the first time stowaways have been found travelling on the rudder of commercial ships to the Canary Islands.
Last year, a 14-year-old Nigerian boy was interviewed by Spain's El País newspaper after surviving two weeks on a ship's rudder. He had also departed from Lagos.
In October 2020, another four people were found by police at Las Palmas after stowing away on the rudder of an oil tanker from Lagos for 10 days.