Paul and Wendy Marshallsea were both given extended sick leave by the Pant and Dowlais Boys and Girls Club where they worked for 10 years.
The couple took the opportunity to visit friends in Australia and were having a barbecue on Bulcock beach when they spotted a fin in the water swimming towards the children playing in the shallows.
Paul dropped his can of lager and ran into the waves to grip the 6ft-long dusky whaler shark and lead it out into deep water.
A TV crew was filming nearby and captured pictures of Paul wading into the shallows.
The pictures were later beamed around the world and Paul became a national hero in Australia where lifeguards praised his bravery.
But charity trustees decided that Paul was avoiding work duties after they saw his footage, where he wrestled the shark, the Sun reported.
But Paul, the charity’s project co-ordinator, said that he is disgusted that the film has been used as evidence to get him sacked.
The dismissal letter to him read, “Whilst unfit to work you were well enough to travel to Australia and, according to recent news footage of yourself in Queensland, you allegedly grabbed a shark by the tail and narrowly missed being bitten by quickly jumping out of the way.
The letter further added that the breakdown of the trustees’ confidence and trust in him and his ability to perform the role is so great that the charity found that the dismissal is the only course of action we can recommend.