The agency will develop a UK positioning for the brand and an advertising campaign to launch later in the year.
Enterprise Rent-A-Car did not previously work with a retained agency on its UK ad account, and instead ran work created overseas. Dare won the business without a pitch.
The car rental company, which launched in the UK in 1994, now operates more than 360 branches and 50,000 vehicles. It is the largest car rental group in the US.
Toby Horry, the managing partner at Dare, said: "Enterprise Rent-A-Car is a fabric brand in the US and we intend to take it to the same place in the UK. We're really excited at the prospect of working together and delighted that it has bought into our new agency model of best-in-breed digital and above the line."
Enterprise Rent-A-Car's media planning and buying account is handled by PHD.