June 6 will be the 80th anniversary of D-Day, when Allied forces stormed the beaches of Normandy, France, the beginning of action that ultimately led to the end of World War II.

The event still looms large in military history — and with watch enthusiasts, who snap up the vintage timepieces that companies such as Longines, Omega and Bulova were authorized to produce for troops at the time.

Now, watch designers from Britain to Australia are planning new watches for the landmark anniversary because, “it’s a very competitive marketplace,” said Don Cochrane, chairman of Vertex Watches.

The company has created the Vertex M36, a 36-millimeter brushed steel watch with a Swiss automatic movement (2,250 pounds, or $2,826). Preorders are to begin May 1 on the Vertex website and at its boutique in London’s Mayfair district, with distribution to start June 6.

What does the name mean? The M is “because all our watches start with an M,” Mr. Cochrane said, noting it is “the same thing that they do in the military,” citing the M16 rifle; the 36 represents the case size.

For Mr. Cochrane, 50, the new watch is a reminder that Vertex was one of the 12 companies authorized by the British military to produce timepieces for its troops. (Vertex was founded in 1912 by his great-grandfather, Claude Lyons, shuttered in 1972 and revived by Mr. Cochrane in 2015.)