The 52-year-old multi-millionaire leapt into action after receiving a call from another vessel off the French south coast near St Tropez.
The drama was revealed on Twitter by Cowell's ex-girlfriend, pop star Sinitta, 43, who is on holiday with the X Factor boss.
When they came nearer to the boat he sent out a smaller boat to rescue the passengers on board and bring them back to his vessel.
The newspaper reported that his staff also helped to pump water out of Slipstream.
A few minutes later she added: 'Everyone ok, no-one hurt.
'Captain won’t let boat sink, petrol in sea etc.
'No tide, so hole plugged!'
A source told the Daily Star: 'He only did what any good person would do.
'If his yacht was in trouble he would want someone to come to his rescue. It was just lucky they happened to be close by.'