The Principality of Sealand, a self-proclaimed micronation founded on a former World War II fort in the North Sea, has issued a number of coins and stamps for collectors.

Sealand coins can be considered souvenirs only or "rounds" since they do not circulate anywhere and are not accepted as currency by any nation.

In 1991 the "Sealand rebel government" (see Forcible takeover) minted antiqued silver SX$100 coins.

In 1994 the "Treasures of the Sea" Sealand dollars were minted, with an orca on the reverse.

[2] In 1994, fewer than 150 copies of the half dollar were accidentally cut with a scalloped edge instead of the normal reeded one.