Diamond Head Theatre is hoping to fill its seats when it opens its season in September, but it will require everyone in the audience to be fully vaccinated against COVID-19.

In an email sent to subscribers Monday, the theater said that “given the current COVID environment, all audience members will be required to provide proof of full vaccination — 14 days after a second dose of an FDA- or WHO-authorized COVID-19 vaccine, or 14 days after a single dose of an approved one-shot vaccine — as well as a government-­issued photo ID.” The email includes the signatures of the theater’s Executive Director Deena Dray and Artistic Director John Rampage.

The Moderna and Pfizer vaccines require two doses three to four weeks apart, which take full effect two weeks after the second dose. The Johnson & Johnson vaccine requires one dose, which also takes full effect two weeks later.

Children under 12, who are still ineligible for vaccines, will be allowed into performances. Masks will be required for all guests, who must wear them at all times, the email said, adding that no decision has been made regarding drinks and snacks in the theater.

The email says the rule will be in place for the Sept. 24 season opener — “Oliver!” — which the theater hopes will attract a capacity crowd of 475. The theater is currently staging “A Chorus Line” to limited capacity, with social distancing and masks required.

The rules are in keeping with theater guidelines across the country, including Broadway, DHT said, adding, “We feel the health of our subscribers and patrons is paramount and this safeguard will allow our customers to feel comfortable coming to our theatre.”