The agency won the brief following a pitch against St Luke's and HHCL Red Cell.
Joshua will develop a campaign to re-establish Swatch as the leading brand in the mass-market watch category. Competition from fashion brands such as Fossil and Guess in Europe and DKNY and Lorus in the US and the UK have put pressure on the Swiss company's position.
The advertising campaign, which breaks in March, will comprise TV, press, poster and interactive elements. The agency will also develop point-of-sale material for its concession stores, located mainly in airports and railway stations. It will focus on the brand's key markets, including the UK, the US, China, Germany and France.
Mitch Levy, the Joshua executive creative director, said: "Swatch were very keen to see a fully integrated idea. We were delighted to deliver one that also has great creative cut-through and will resonate strongly in all markets."