A law was passed in July 2015 in the state of Hawaii that allows medical marijuana dispensaries and licensees are permitted to begin dispensing medical marijuana no sooner than mid July 2016, after they receive approval from the state. If you are not a patient, marijuana use and posession is classified as a misdemeanor.
Currently recreational marijuana is both illegal for locals and travelers. They only law difference is that locals have access to what many call “The Blue Card” which is their system of medical marijuana. Travelers, even if they have a medical marijuana card from their home state, can not apply for a medical marijuana card while in Hawaii and the card they have from their home state is useless.
Medical marijuana dispensaries are open in Hawaii for both locals and tourists. If you need marijuana for pleasure, you need to get it from a local and this is illegal. The law is same for both the locals and the travellers. Also remember that you cannot fly with the herb, so you cannot take it from home as well.