The metre-long pythons bit their way out of a small cardboard box at the main post office in the central German city of Darmstadt, according to police.
A postal worker noticed one of the pythons after it emerged from a box addressed to the eastern German state of Thuringia. The box was only 50 centimetres by 38 centimetres by 23 centimetres - about the size of a shoebox for a pair of knee-high boots.
She alarmed co-workers, who found the other two reptiles still nested inside the relatively small box.
The snakes were given into the custody of a reptile house, where the keeper said the animals seemed underfed.
Meanwhile a few hours' drive to the north, in the city of Essen, police hunting for a boa constrictor reported by a young boy on Thursday had to hoist a pre-fabricated garage from its foundation. The two-metre-long snake was hiding underneath in a rabbit warren, police said.
Police are seeking the owners of all four reptiles. They are also trying to determine who mailed the package with the three pythons.