You can find the legal information about travelling with your pets within the EU at Regulation (EU) No 576/2013. This regulation applies to the non-commercial movement of pet animals into a Member State from another Member State or from a territory or a third country. It does not apply to the movement of pets within one EU country.
This same Regulation establishes a list of animal species to which harmonised animal health requirements apply when animals of those species are kept as pet animals and moved for non-commercial purposes. This list takes account of their susceptibility to or role in the epidemiology of rabies.
Dogs, cats and ferrets are animals of species susceptible to rabies and are listed in Part A of Annex I to Regulation (EU) No 576/2013.
Pending the adoption of Union rules for the non-commercial movement of animals of the species listed in Part B of Annex I to Regulation (EU) No 576/2013, national rules apply.
Regulation (EU) No 576/2013 regulates the non-commercial movement of a pet animal which accompanies its owner where its owner moves and is under his direct responsibility. The non-commercial movement of the pet animal may take place up to five days before or after the movement of the owner, in which case the non-commercial movement of the pet animal is carried out under the responsibility of a natural person who has authorisation in writing from the owner to carry out the non-commercial movement of the pet animal on his behalf
The maximum number of pet animals (dogs, cats or ferrets) which may be moved for non-commercial purposes is 5.
Exceptionally, the maximum number may exceed 5 only when all of the following conditions are met:
the movement is for the purpose of participating in competitions, exhibitions or sporting events (or in training for such events)
written evidence is provided that the animals are registered either to attend an event or with an organisation organising such events
the animals are more than six months old.
Where the maximum number exceeds 5 but the above listed conditions are not met, dogs, cats or ferrets must comply with the animal health conditions applicable to trade in or import into the Union.
Where the non-commercial movement of pet animals is not caused by the movement of the owner, whatever the number of pet animals, the animals are to comply with the animal health conditions applicable to trade in or import into the Union of such animals.