Answer:
Yes, but oolong tea is not as widely available in many parts of the U.S.
Most supermarkets stock one or two brands of oolong teas, but they are typically generic oolongs and are not of the highest quality. Asian stores, especially those catering to a Chinese customer base, typically carry oolong teas as oolong is popular in China and many other parts of southeast Asia. Health food stores sometimes sell oolong tea.
The best place to purchase oolong tea is a tea shop that specializes in loose tea, if you are lucky enough to live near one. There are also a large number of online retailers selling oolong tea. In most parts of the U.S., the internet is the best and easiest way to buy quality oolong tea.