First Nations activist Audrey Siegl, who lives in Vancouver, wore traditional Musqueam regalia while drumming in front of the 90-metre tall rig, according to photos and video provided by Greenpeace.
The Greenpeace video also showed swimmers in wetsuits, holding a protest sign that said "People vs. Oil," appearing close to the massive rig as it kept plowing through water about 40 nautical miles west of Vancouver Island.
The Polar Pioneer rig left Seattle Monday, despite efforts by two dozen protesters — including a Seattle city councillor — to block the drill rig from leaving port.
The protesters were temporarily detailed by the U.S. Coast Guard and issued violation notices that carry fines.
In May, the U.S. government approved Shell's multi-year plan to drill for oil in the Chukchi Sea, about 110 kilometres northwest of the village of Wainwright, Alaska, despite objections from environment groups and others.