The Charcot expeditions visited Greenland and Iceland annually on scientific studies. The 1935 expedition carried an official mail franked by a private vignette and Iceland postage. The following year the ship and all hands were lost in a storm off Iceland.

Jean Charcot attracted the French scientific community to continue work in the polar regions. Each year he sailed to Iceland where he serviced stations and projects. In 1935, his ship was destroyed in a storm as he left Reykjavik harbor. His work was continued by the "Scientific Service to the Sea", illustrated by this cover.

Thor Solberg flew a single engine amphibian plane from New York to Denmark in easy stages during August and September of 1935 to prove the navigational ability of aircraft in the Arctic.

Covers were carried outside the mail, but received a transit mark in Greenland. The covers were returned in regular mail from Kobenhaven.

The Mac Gregor Expedition of 1937 intended to establish a radio station on Ellesmere Island in northern Canada. Their initial base was at Reindeer Point in Greenland where the mail was canceled on March 27, 1938, where they were finally forced to conduct their work.

A Russian party, led by Ivan Pappanin, was placed on the North Pole by aircraft on May 19, 1937 to study polar drift. The party had to be removed by icebreakers on February 19, 1938 at 70° 54' N latitude. Mail was not handled during the drift, but commemorative covers were issued on their return.