So, it really depends. (I am not a lawyer) 1. Usually you have a probation period (Probezeit) in your contract which allows to resign with 2 weeks notice time

So, it really depends. (I am not a lawyer) 1. Usually you have a probation period (Probezeit) in your contract which allows to resign with 2 weeks notice time for X months (usually 6 months), so you could resign right when you start. During that probation period also your employer could end the employment with two weeks notice. Your contract forbids resigning before you start, so you would need to resign on your first day. 2. You can ask for nullifying the contract (Aufhebungsvertrag). 3. Depending on your contract, there could be a penalty in the contract if you resign early. I think option two, nullifying the contract is the most honest option. Just be direct with the company you have signed with that you have a better offer.