Can I start working in Czechia as soon as I arrive on an employee card?

Holding an approval or an entry visa is not the same as being free to start work. Employment may only begin once the employee card process is complete and the Ministry has confirmed your status, apart from limited exceptions provided for in law.

You also cannot work during a visa-free stay. After arriving, you must register at the relevant office within the required period (typically 30 days) and complete the biometric and collection steps. Starting work before you are authorised can put your status at risk.