The quay at Rothera Research Station is used by the British Antarctic Survey (BAS) to moor its research ships.
Marine engineering, diving and fabrication company Ocean Kinetics and civil engineers Arch Henderson have been called in.
The Rothera station was established in 1975.
It is thought to be the first underwater welding job of its kind to take place below the Antarctic Circle.
Michael Fox, the marine projects director for Ocean Kinetics, said: "We worked quickly to mobilise and meet the sailing deadline.
"In that time we fabricated and supplied all the materials needed for the contract and provided all the necessary diving equipment and plant to carry out the works.
"Taking into consideration how remote the location of the project is, we had to send plenty of spare parts along with back up welding sets and generators.
"If something was to breakdown there it would take weeks, if not months, to ship in a replacement.
"This is an exciting project for both companies and we think we might be the first UK company to carry out underwater welding within the Antarctic Circle for BAS."
Arch Henderson, which was established in 1919, worked with Ocean Kinetics to design the solution to repair the quay.
Arch Henderson partner Andy Martin said: "It is a very interesting project and our first opportunity to work in the Antarctic."
Companies from Shetland and Aberdeen have been awarded an Antarctic contract to repair a quayside which was damaged by an iceberg.