The Greenpeace flagship Rainbow Warrior and a group of 80 activists are blocking the Russian Gazprom's oil tanker, Mikhail Ulyanov, from delivering oil from Arctic waters to Rotterdam harbour.
The block is an attempt to impose a ban on offshore oil drilling in the Arctic, both in Russia and elsewhere in the world, and to promote the use of new energy sources.
The incident took place when the 258m long tanker was carrying oil from Gazprom's Prirazlomanaya platform located in the Arctic Pechora Sea.
The activists painted 'No Arctic Oil' on the hull of the tanker while others prevented the ship from mooring by placing themselves in inflatables between the quay wall and the tanker.
An activist Faiza Oulahsen said: "Thirty of us went to prison for shining a light on this dangerous Arctic oil, and we refuse to be intimidated. This tanker is the first sign of a reckless new push to exploit the Arctic, a place of incredible beauty which is melting before our eyes."
In 2013, Gazprom's Prirazlomanaya platform was the site of a similar protest that saw a high-profile intervention and resistance from the Russian authorities.
Greenpeace International executive director Kumi Naidoo said: "Arctic oil represents a dangerous new form of dependence on Russia's state-owned energy giants at the very moment when we should be breaking free of their influence."
"We cannot hope for any kind of ethical foreign policy while our governments remain hopelessly dependent on companies like BP, Shell and Gazprom."