28 July 2004
Around 2003/2004, a counterfeit R5 coin was circulating in South Africa. Although not an exact match of the original, the coin was convincing enough to fool many people. This prompted the Reserve Bank to redesign the coin in order to outsmart counterfeiters. By 28 July 2004, South Africa had a new R5 coin. The new coin was bi-metal, with a silver coloured border and a bronze coloured center. It was also thicker and heavier that the old coin. The coin went into circulation on 2 August 2004.  
References

South Africa.info South Africa's new R5 coin [online] Available at: www.southafrica.info [Accessed on 5 July 2012]|SA Mint CIRCULATION COINS [online] Available at: www.samint.co.za [Accessed on 5 July 2012]