The Bianconeri has also revealed that a further €3.1m (£2.78m) will be included into the deal dependent on certain terms being met during the length of the four year contact.
The length of time that the Gunners will have to wait to receive the transfer fee in full is not unusual, but it is more uncommon for a club to publicly state the finer details of a transfer.
Arsenal will certainly not mind the numbers being made public. The London club managed to hold out for almost the €16m asking price they had been demanding for the 27 year old. If Szczesny becomes a first team regular after Gianluigi Buffon retires next summer, the Gunners will be confident of receiving the full €15.3m (£13.7m).