USA FAR 91.703 states:
§91.703 Operations of civil aircraft of U.S. registry outside of the United States.
(a) Each person operating a civil aircraft of U.S. registry outside of the United States shall—
(1) When over the high seas, comply with Annex 2 (Rules of the Air) to the Convention on International Civil Aviation and with §§91.117(c), 91.127, 91.129, and 91.131;
(2) When within a foreign country, comply with the regulations relating to the flight and maneuver of aircraft there in force;
(there is more but you can go read it if you wish)
Obtaining and then understanding the huge volume of information can be a daunting task. Unfortunately, we have discovered, after decades of international flying, that the information in these AIP's is oftentimes incomplete or just flat wrong. The implications of that is that any Airway Manual supplier (I won't mention names) that bases their documentation on AIP's is going to suffer from the same incomplete or incorrect data. This raises the bar even higher. This is why having places where we can post factual and timely information is essential. I won't pick on any country to give examples but just suffice it to say that it happens.
With this new topic, we can all continue to share our doubts, concerns, questions and hopefully factual and accurate answers to these.