The Brussels prosecutor's office confirmed that the region's former president and his sacked ministers surrendered after Spain issued a warrant for their arrest.
He said that they have not been arrested and that Puigdemont and the four members of his disbanded Cabinet will be heard by an investigative judge later in the day.
The charges the leaders face include sedition, rebellion, misuse of funds, abuse of authority and contempt.
Mr Dejemeppe said that the entire process from arrest to extradition could take more than 60 days.More news: Apple reports earnings after the bell
The move has seen Madrid take control of Catalonia's civil service, police force and finances and call the snap election, which could see as many as 150 of the region's top officials replaced.
Mr Puigdemont's lawyer, Paul Bekaert, has already announced that he will "appeal" if a Belgian judge accepts the expected arrest warrant from the National Court judge Carmen Lamela. A ninth spent a night in jail and was freed after posting bail.
Belgium, where a European arrest warrant can be blocked for several mainly procedural reasons, will have a maximum of three months to decide whether to send Puigdemont back to Spain.
Political forces in Catalonia are hurriedly jockeying for position to start a campaign that promises to be as bitter as it is decisive to Spain's worst institutional crisis in almost four decades.
Parties have until Tuesday to register as coalitions or they must run separately.More news: Prepare For A Stormy Sunday; Wind, Flood Watches In Effect
An opinion poll published on Tuesday showed Junts Pel Si would win in December with 35.2 percent if the vote was held immediately and would likely reach a parliamentary majority if it stuck with its current pact with far-left party CUP. But Mas said the main goals of secession supporters must be recovering self-rule and the release of the jailed separatists.
"Under these exceptional circumstances that our country is going through, don't we have to substitute the normal and logical competition for the cooperation we all need?"
DW reporter Charlotte Chelsom-Pill, who was at the scene, said demonstrators chanted "We are not afraid" as they waited for the return of the six Catalan officials who appeared in the Supreme Court.
Puigdemont married a fellow journalist, Marcela Topor, in 2000 and together they have two daughters.More news: Presidential hopeful Rand Paul attacked at his Kentucky home