On base of European Council decision No. 368/2004 ES, regarding preliminary execution of European Economic Space, the citizens of Czech Republic can travel to Liechtenstein, since 1st May 2004, with valid passports or valid personal identity cards. Since 1st January 2006, the new law, regarding travel documents, came into operation (published under No. 559/2004). The travellers can leave the territory of Czech Republic, with a target in Europen Union countries, with personal identity cards, containing readable data, as the only travelling documents.
Anyway, the personal identity card is a travelling document for the holder only. So, Interior Ministry does not recommend that a citizen of Czech Republic, younger than 15 years of age, travelling together with their parents, and registered in their travel documents, could travel without his own travelling document, on base of registration in parents´ travel document only.
The drivers of motor-vehicles need for their presentation valid driving licence, valid certification concerning technical ability of the vehicle (so called small technical certificate), a document regarding international security, as far as the legal responsability for damages, caused by operation of motor vehicle (so called green card).
Information and warnings on travelling abroad is to be found HERE.