There is no immigration check HNL-GUM or GUM-SPN. However there is an admissibility eligibility check SPN-GUM and GUM-HNL. Documents proving your status will be helpful.
Originally Posted by
Box5
Guam is US territory but some proof of citizen is useful because people from Red China go to Guam without a visa and the U.S. is afraid they will sneak off the island. No joke.
No that isn't happening yet. Mainland Chinese can only go to the CNMI without a visa. HK/Macao Chinese can go to both Guam and the CNMI without a visa or ESTA.
Originally Posted by
FlyingUnderTheRadar
If one if flying the island hopper, the chances are very high that one will not only divert to a foreign county but will actually land in one regardless, Fed. States of Micronesia.
Actually two. The Marshall Islands too.