Due to the influence of the Atlantic Ocean, Lisbon has a pleasant climate throughout the year. The agreeable temperatures in the summer months are an open invitation for a walk by the river, or to spend an afternoon in one of the many street cafés to be found all over the city. Although the temperatures may fall somewhat in the autumn and winter months, sunshine is almost always a constant feature.

Useful information

For more details about the climate and other useful information to plan your visit to Lisbon, visit the Lisbon Tourist information.

Congress language

The official language of the Congress is English.

Letter of invitation

Letters of invitation required to meet the administrative and legal regulations for visas of some countries are available to participants upon written requests. Please inform the congress secretariat for further processing.

Upon request, the Secretariat of the 13th ECNDT Conference (ECNDT 2023) will send a personal invitation letter to participants. This invitation is meant to help visitors to raise travel funds or to obtain a visa, and is not a commitment on the part of the organisers to provide any financial support. Please contact us and email your request with full name, postal address and passport number to

We are unable to send invitation letters directly to consulates. Invitation letters are prepared solely for individuals and are mailed directly to them.

Kindly note that, due to a high volume of requests, it may take up to 10 working days for the letter to be ready. Please take this into consideration when applying for a visa and ask for the letter in advance.


A valid passport (or identity card for European Community nationals) is required.

Passport and Visa Requirements

Citizens of the European Union, Bulgaria, Cyprus, Iceland, Liechtenstein, Norway, Romania and Switzerland only need an identity card to enter Portugal.

For visits of less than 90 days, a passport valid for at least three months after the end of their stay is necessary for visitors from Albania, Andorra, Antigua and Barbuda, Argentina, Australia, Bahamas, Barbados, Bosnia-Herzegovina, Brazil, Brunei, Canada, Chile, Costa Rica, Croatia, Guatemala, Holy See, Honduras, Israel, Japan, Macedonia, Malaysia, Mauritius, Mexico, Monaco, Montenegro, New Zealand, Nicaragua, Panama, Paraguay, Saint Kitts and Nevis, San Marino, Serbia, Seychelles, Singapore, South Korea, United States of America, Uruguay, Venezuela, Special Administrative Regions of the People’s Republic of China in Hong Kong and Macao and Taiwan territorial Authority.

Citizens from countries not mentioned above need a visa to enter Portugal, which may be requested at the Portuguese Embassy or Consulate of their country, or another EU Embassy, for stays of up to 90 days.

Under the terms of the Convention Implementing the Schengen Agreement, flights between Schengen states are considered to be internal flights and passengers do not need to obtain another visa.

Portuguese Embassies and Consulates Abroad

Contact Information:

Organising Secretariat

AIM Group International – Lisbon Office