The Saint Lawrence Seaway is probably best known to philatelists for the famous invert variety of the commemorative issued by Canada on June 26, 1959 to celebrate the opening of the system. A mint copy sold in 2020 at Sparks Auctions for CDN$10 530 and used copy for CDN$5 610. According the editors of the 1999 edition of the Unitrade Specialized Catalogue of Canadian Stamps approximately 400 copies of the Seaway Comemorative were issued with inverted centres. There are fourteen recorded covers or cards with this error properly used. The fake presented below was probably intended as a prank: the unlikely placement of a regular stamp beside an invert is the first clue that this is not real. What is interesting about this fake is that it passed through the mail. Sadly, my stamp budget will not permit me to add the real stamp to my collection, but this page will present more affordable souvenirs of the error.

This cover mailed from Sackville, New Brunswick to Belmont Station, Nova Scotia is franked with
a normal Canadian St. Lawrence Seaway commemorative and one where the centre has been cut out
and inverted along with a definitive would have been more than sufficient to cover postage.

On January 2, 2015 Antigua and Barbuda issued a souvenir sheet depicting
the famous "St. Lawrence Seaway invert" as part of its rare stamps series.