Greece is a Member-State of the European Union and has ratified the Schengen Agreement. Citizens traveling inside the E.U. just need to display their police I.D. Card without the need of a passport. However, a passport is necessary for a number of other transactions, such as currency exchange, purchases, etc.
Visas are not required by citizens of Member-States of the Schengen Agreement. Greece follows the provisions of the Schengen Agreement, which abolished controls on common internal lands, at air and sea borders and allows Member-State citizens to travel around without a visa for a short stay period of up to three (3) months. However, airlines and other carriers require a valid passport and/or police I.D. Card or other form of official identification means.
Citizens of the majority of the countries that are not Member-States of the Schengen Agreement require a visa to enter Greece and the E.U. Visitors from these countries can obtain further information from the Hellenic Embassies or Consulates in their countries, or even from their travel agencies.
Visas are not required by holders of valid passports from the following non-E.U. countries if they want to visit Greece and remain in the country for up to 3 months (90 days) within a chronological period of 6 months:

Countries
Andorra Chile Israel Vatican South Korea
Argentina Costa Rica Japan Nicaragua USA
Australia Croatia Malaysia Panama Uruguay
Brazil El Salvador Mexico Paraguay Venezuela
Brunei Guatemala Monaco Saint Marino
Canada Honduras New Zealand Singapore

Note: During their stay in Greece, visitors with a visa must also have suitable insurance coverage for emergency medical or other needs.

Consulates in Rhodes island
If any serious problem arises, the following consulates will be willing to assist their nationals:

Consulate of Address Phone Fax
Austria 21 Iroon Polytehneiou Str, Rhodes 22410 25455
Belgium 35 Kos Str, Rhodes 22410 24661
Denmark 5th km. Rhodes-Lindos Ave, Rhodes 22410 94488
Finland 25 G. Leontos Str, Rhodes 22410 35780 22410 36696
France Ippoton Str, Medieval City, Rhodes 22410 22318 22410 77488
Germany 55 Amerikis Str, Rhodes 22410 37125
Hungary 13 D. Theodoraki Str, Rhodes 22410 27108
Italy Ippoton Str, Medieval Town, Rhodes 22410 27342 22410 33980
Norway 54 Orfanidou Str, Rhodes 22410 28816
The Netherlands 25 Alexandrou Diakou Str, Rhodes 22410 31571
Spain 13 D. Theodoraki Str, Rhodes 22410 25698 22410 73522
Sweden 20 D. Theodoraki Str, 85100 Rhodes 22410 31822
Switzerland 108 G.Seferi Str, Rhodes 22410 78130 22410 78131
Turkey 10-12, Iroon Polytehneiou Str, Rhodes 22410 23362 22410 27472
United Kingdom 29 Gr. Lampraki Str, Rhodes 22410 22005 22410 24473