Switzerland's Federal Criminal Court sentenced the Czechs, only two of whom were present in court, to between three years and four-and-a-half years in prison, the Swiss news agency ATS reported Friday.
The Belgian, Jacques de Groote, was fined, but his penalty was suspended.
Czech media named the five businessmen as Marek Cmejla, Jiri Divis, Antonin Kolacek, Oldrich Klimecky and Petr Kraus.
The men were accused of stealing and laundering money siphoned from Czech mining company Mosteck Uhelna Spolecnost between 1997 and 2003.
The five Czechs, including former board members, had managed to gain control of 97 percent of the company.
They went on to launder more than a billion Swiss francs.
The money was stashed in bank accounts in Switzerland and neighbouring Liechtenstein, in the name of more than 30 firms based in the Bahamas, the Isle of Man and other offshore havens.
Investigators located and froze 550 million francs ($604 million) which had been stashed in Switzerland.
De Groote, previously an administrator at the International Monetary Fund, was accused of providing a veneer of credibility, with the cash purportedly coming from investors.
ATS reported that he received almost one million Swiss francs for his role in the scam.
The money-laundering case was launched in 2005.
The accused men had pleaded not guilty, and still have the option of asking Switzerland's Supreme Court to overturn their conviction.