A Santa Monica-based booking service that offers day passes to hotels and resorts raised $8.7 million in a new funding round, according to a Securities and Exchange Commission filing on Aug. 19.

ResortPass Inc. is courting people who yearn to dive into a sky blue pool or relax in a deluxe spa without booking a hotel room. It’s one of a growing number of online booking companies, including Dayaxe.com and DayPass, selling the idea of a poolside “daycation.”

Three-year-old ResortPass, which was co-founded by Chief Executive Amanda Szabo, has raised $12.7 million to date, according to data from Pitchbook Data Inc. Company officials could not be reached, but filings show the funds came from 14 investors.

ResortPass sells day passes for luxury hotels like the W Hollywood, the Viceroy Santa Monica and the Kimpton Hotel Palomar. Busier days and weekends are more expensive to book, with the service using a congestion-pricing model similar to that adopted by ride-hailing service companies such as Uber Technologies Inc.

According to the ResortPass website, passes in Los Angeles start at $20 for pool access and rise to $450 for a 12-person cabana at the Viceroy, which also requires a $1,100 food and drink minimum.

“Hotels are always looking for ways to add on revenue,” said James Stockdale, who specializes in hotels at real estate investment firm Jones Lang LaSalle Inc. “We continue to see how the industry is matching or trying to match with the coworking companies to find revenue for underutilized space.”

Manufacturing, retail and trade reporter Rachel Uranga can be reached at [email protected] or (323) 556-8351. Follow her on Twitter @racheluranga.