Singapore has only been a country since 1965. It has only had its own coins since 1967. This ten-cent coin is from 1968, and belongs to the first series of Singapore coins, which featured sea animals.
The second series (introduced in 1985) featured flowers. There were two versions of the coat of arms, one with the banner bowed upwards and one with the banner hanging down. Supposedly the coat of arms was changed for better feng shui, because when the banner is hanging down, it looks like a smile rather than a frown. The octagon inscribed in the circular one-dollar coin is thought to be lucky.
The third series of coins (introduced in 2013, after I came to Singapore) involved changes in the metal composition and size of the coins as well as the designs, which are now more architectural.
The new coins have mostly displaced both second series designs, though I still get some mixed in with my change. It is quite rare to see a first series coin in circulation now.
Learn more about Singapore’s coins: