Egypt and Kenya specialist African Safari Club has ceased trading with 500 clients overseas and an unknown number of forward bookings.
The Civil Aviation Authority confirmed the tour operator had folded late on Wednesday, but said all those abroad would be able to complete their holidays.
Most clients are in Egypt or Kenya and are due to return by next week. Bromley-based African Safari Club specialised in Nile cruises, Indian Ocean cruises and safaris.
It had also operated a small ocean cruise ship MS Royal Star of its own offering cruises to Seychelles, Mauritius, Zanzibar, Madagascar and South Africa.
It had previously flown its own aircraft with a distinctive Zebra livery from Gatwick, but for the past 18 months had operated a charter with Monarch Airlines.
African Safari Club, which was an Abta member, is the fifth long-haul Atol-holder to fail this year.
In October 2009 it was critcised after being accused of not paying staff at its Vasco da Gama, Flamingo Beach and Dolphin hotels in Shanzu Beach.