Consular assistance is help and advice provided by the diplomatic agents of a country to citizens of that country who are living or traveling overseas.

Such assistance may take the form of:

• provision of replacement travel document
  Travel document
  A travel document is an identity document issued by a government or international treaty organization to facilitate the movement of individuals or small groups of persons across international boundaries...
  
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• advice and support in the case of an accident, serious illness or death
• advice and support to victims of serious crime overseas, and arranging for next-of-kin to be informed
• visitation contact with incarcerated nationals
• liaison with local police officials in the case of nationals abducted or missing overseas
• loans to distressed travellers
• help during crises, such as civil unrest and natural disasters
• facilitating the overseas payment of social welfare benefits
• registering citizen births abroad
• providing a list of local doctors and lawyers
• supervising their flag vessels in foreign harbours

Such assistance commonly does not extend to:

• storing luggage or valuables
• intervening in commercial disputes on behalf of their nationals
• providing travel agency, banking, or postal services
• money changing
• translation and interpreting services
• legal advice or advocacy
• negotiation of special treatment, bail, or early release from prison
• criminal investigation
• employment services

Vienna Convention on Consular Relations

At Article 5, the Convention gives the most broad, detailed, and internationally-accepted definition of 'consular functions':