There are three series of coins in circulation. All are valid.
The first series depicts King Albert II in the inner part of the coin, while the royal monogram - a capital "A" underneath a crown - among 12 stars, symbolising Europe, as well as the year of issuance appear in the outer part.
In 2008, Belgium slightly modified the design in order to comply with the European Commission's guidelines. The coins of the second series also show King Albert II, but the royal monogram and the year of issuance now appear in the inner part of the coin, as do the mint marks and the country code for Belgium, "BE".
In 2014, Belgium introduced the third series of euro coins, which show King Philippe, his royal monogram "FP" and the country code for Belgium, "BE". The mint marks appear on either side of the year of issuance.
Min Mark of the Royal Mint of Belgium: head of archangel Micheal with a cross.
1999-2009 Rigth to the timestamp
2010-... Left to the timestamp
Director of the Royal Mint of Belgium, Romain Coenen: scales.
Left to the timestamp
Director of the Royal Mint of Belgium, Serge Lesens: feather
Rigth to the timestamp