Fifteen pupils from Tom Hood College in Leytonstone, north-east London, went to Sir James Smith's School in Camelford, then visited a farm, cycled along a disused railway line and sampled cream teas.
Previously, 14 Cornish pupils spent a week in London, sailing the Thames, visiting Parliament, taking in a show and dining at Nando's.
Alfie Boulton, 13, from Cornwall, said: "I thought London would be all grey buildings and cars, and just boring - and it was. But I thought the people would be hardcore, loser gangsters, but they were just normal, only with different accents."
Tony Kloska, deputy head of Sir James Smith's, said challenging stereotypes was the project's aim.
James Sevitt, of Citizenship Foundation, the education charity that organised the exchange, agreed: "Diversity is often approached through the lens of ethnicity. But rural-urban differences are as important as ethnic diversity."