Protected areas that meet across international borders provide important collaborative opportunities between managers and scientists in neighbouring countries and provide possibilities for promoting conservation and sustainable management across politically divided ecosystems. Various terms are used to describe these areas; 'transboundary protected areas complexes', 'transfrontier protected areas', 'adjoining protected areas' and 'peace parks' are the most common.

The International Union for Conservation of Nature (IUCN) describes transboundary protected areas as:

“an area of land and/or sea that straddles one or more borders between states, sub-national units such as provinces and regions, autonomous areas and/or areas beyond the limit of national sovereignty or jurisdiction, whose constituent parts are especially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources, and managed cooperatively through legal or other effective means” - Sandwith, T., Shine, C., Hamilton, L., and Sheppard, D. (2001) Transboundary Protected Areas for Peace and Cooperation. IUCN, Gland, Switzerland and Cambridge, UK

The main types of recognised transboundary protected areas are as follows:

1. A protected area that encompasses two or more countries’ territories:
A single protected area that is shared between two or more countries, crossing international boundaries, and that involves cooperative management.

2. Two or more adjoining protected areas across a national boundary:
Two or more protected areas in different countries that share a common border, being managed cooperatively for common conservation aims.

3. A cluster of protected areas and the intervening land:
Is more ambitious in that it attempts to balance strict protection with sustainable management in buffer zones and other parts of the landscape.

4. A cluster of separated protected areas without intervening land:
In practice, it is not always politically or practically possible to include intervening land and some successful transboundary initiatives have involved protected areas that are geographically separated but share common ecology or problems, and usually have some interchange between species.

5. A trans-border area including proposed protected areas:
Some transboundary initiatives have started with protected areas in one country or region, with the hope of extending protection across the border, but without any formal agreement. This might be a transitional stage, with the area later becoming, for example, two or more contiguous areas across a national boundary.

6. A protected area in one country aided by sympathetic land use over the border:
Sometimes there will be no realistic expectation (or perhaps no need) for protected areas on both sides of a border, but a need for sympathetic management in one country to safeguard a protected area in its neighbour's country.