The 1er RIMa is a light armoured unit, since 1986, alike with the régiment d'infanterie-chars de marine RICM.

Heir to the Compagnie Ordinaire de la Mer created in 1622 by Richelieu, the regiment was created by a Royal Decree in 1822 at the corps of the French Naval Ministry (French: Ministère de la Marine).

The evolution of the unit's name: The regiment is heir to the 1st Free French Division and the battalion of the Pacific which combat engaged at Bir Hakeim.

The division immediately engaged the theatre, in the sector of Sun-sur-Meuse, Stenay, Martincourt, Aviot, Breux north of Verdun, at the level of cote 304 and Mort Homme, lieu of harsh combats in 1916–1917, where combats concentrated.

At 0630, the cote was crowned, despite a relentless resistance, the armoured contingents crossed the bridge of Bethoncout in direction of Esnes.

The regiment has participated in all major operations of the French Army (Lebanon, Bosnia, Kosovo, Chad, Côte d'Ivoire, Central African Republic, Afghanistan).

[1] In 2010 members of the regiment were deployed in Guadeloupe and Djibouti or in operations in Kosovo and Afghanistan.

[1] The anniversary is celebrated for combats in Bazeilles, the village which was apprehended and abandoned four consecutive times under orders, respectively on August 31 and September 1, 1870.