The Oasis Theater, previously the Hermiston Playhouse Theater located on Main Street Hermiston (1), was purchased by the Oasis Theater Company in July of 1930 by Oasis Theater Incorporated (2). It was refurbished and redecorated from its pre-Oasis state and included the installation of two Vitaphones and completely new modern equipment, with Lloyd A. Moore and R. C. Begg acting as managers at its opening (3).
The Oasis officially opened its doors on Friday, August 1st, and Saturday, August 2nd, 1930. With a schedule of shows on Friday, Saturday, Sunday, and Monday, the Oasis celebrated its opening days on Friday, August 1st, and Saturday, August 2nd, 1930, with two screenings of The Isle of the Lost Ships starring Jason Robards Sr., Virginia Valli, and Noah Beery Sr. Wrapping up the opening weekend, there was a screening of Gold Diggers of Broadway on Monday. With a schedule of showings from Friday through Monday, the theater quickly became part of the community, once again serving as a center for community engagement through events such as showing high school plays (4), and class productions along with other events held at the theater (5).

Hall, Sharon. Hermiston, Oregon - History in Photos. Front photo of Oasis theater, Date Unknown. Facebook, 17 March. 2017, https://www.facebook.com/photo/?fbid=148003591651235&set=gm.10160842459251069&idorvanity=123999921068. (13)

The Hermiston Herald, July 31, 1930. p.6. Historic Oregon Newspapers
In 1931, the theater continued this trend with Moore buying R. C. Begg's half ownership of the Oasis Theatre Company, which led to him becoming the owner of the company (6). The Oasis continued to connect with the community and held screenings, with an update in 1935 when the theater underwent major upgrades. The Hermiston Herald described that there had been improvements in the flooring, seating changes, new cushions, a new sound amplifier, and an air system for both heating and cooling (7).
The theater continued booming throughout the decade, with new, higher-quality seating being updated and new carpeting installed in 1939 (8). Lloyd went on to operate the theater with his wife, and it continued to subscribe to exhibitor trade journals until at least 1952 (9). Lloyd was spotted on Portland's exhibitors' row until 1948 (10). He went on to open and operate the Hermiston drive-in in 1949 alongside the Oasis, which most likely led to its demise (11).
Due to the lack of sources in public news and trade journals, there isn't evidence of the news of the oasis following 1945. However, the oasis remained a part of the Hermiston community until the mid-1970s, with ads in local high school yearbooks in 1972 (12). Community members continue to reminisce about the theater in historical groups, sharing memories of a mothers' and babies' crying room, waiting in long lines, watching matinees, and sharing first kisses, and watching horror movies that reflect its deep connection to the community (13). While there is no exact date, it can be estimated the theater ended operations between 1972 and 1975 and was demolished around 1976 based on personal stories (14).