it's sometimes awkward when asked this question because Cantonese-speakers usually say 'bye' just as people who speak English do--by saying 'bye' or 'byebye.' But since you're probably asking for some phrase in Chinese/Cantonese, there's one pronounced "zoy geen"--literally meaning 'see you again'
In Cantonese, you can say "再見" (joi gin) to mean bye bye.
There are many useful phrases in Cantonese. Transliterated to English the most common is hello: "wei." Thank you is "m goi." Bye bye is similar using "bai bai."
Most people in Hong Kong merely say "bye-bye", although in proper Cantonese it should be "再見" (pronounced joi-gin).
In written form it would be 再見 (joi gin) But people usually say 拜拜 (bye bye)<--yes its just the same as English.
Cantonese people mainly speak Cantonese, a Chinese dialect. Additionally, many Cantonese people may also speak Mandarin, which is the official language of China, as well as English, due to Hong Kong's history as a British colony.
Here are some examples of Cantonese.
'Cat' in Cantonese is 'Maau.'
'Flower' in Cantonese is 'Faa.'
In Cantonese, "king" is pronounced as "王" (wong4).
'Basketball' in Cantonese is 'Laam Kau.'
si do be lei, is strawberry in cantonese :)
Cantonese speakers may be able to understand some Mandarin Chinese due to similarities in vocabulary and grammar, but the two languages are distinct. Differences in pronunciation and tones can make it challenging for Cantonese speakers to fully understand Mandarin, and vice versa.