From April 30th, telecom companies will be able to charge a maximum of €0.06 per minute on top of the domestic price for calls, €0.02 for texts, and €0.06 per megabyte of data.
Accepting a call will be capped at €0.012 per minute.
Prices for German customers are slightly higher than those laid out in the new regulations as they include VAT.
Total ban by 2017
Roaming fees are set to disappear completely by June 2017, ten years after the European Commission first looked into reducing costs for mobile calls within the EU.
But the mobile operators could still manage to claw back some of the cash if they succeed in obtaining exceptions to some of the new rules.
German consumer organizations also warn that it's unclear how the new rules will apply to customers on flat-rate mobile plans.
Operators may only charge the permitted extra fee on top of the user's monthly payment – or could introduce small print to make flat rates valid in the user's home country only, allowing them to set a minute-by-minute tariff for calls abroad.
Some operators, though, have responded to customers' anger at roaming fees by introducing monthly packages that include some or even unlimited free roaming.