Renters are the newest group trying to cash in on the profitability of Oahu’s vacation rental market by subleasing all or part of their units to visitors.

It’s a legal way to make extra bucks or subsidize rent if the tenant has the landlord’s permission and the property is in one of Oahu’s resort districts or has a city-issued non-conforming use certificate. But legal opportunities on Oahu are limited by a 1989 city moratorium that has reduced certificates to 775 vacation rentals and 41 bed-and-breakfast homes.

Tenants who sublease their units as vacation rental properties without the owner’s permission face eviction. Those who break city rules also face penalties starting with an initial fine of $1,000 and up to $1,000 a day for continued violations.

But for some, the possible fines are a risk they are willing to take. One-bedroom rentals typically cost $1,000 to $2,000 a month, but they can fetch upwards of $1,000 a week when sold to vacationers, said Hawaii real estate analyst Stephany Sofos.

“I had a tenant who moved out without my knowledge. I was shocked to find out she had put the unit on Craigslist and Airbnb,” Sofos said. “She was renting from me for $1,500 a month and getting $1,000 a week. I told her that she had to leave or face eviction.”

Another reason for this latest vacation rental twist is that it’s hard for the city to prove illegal use. Also, rule-breakers typically don’t get hit with major penalties. Still, it happens.

Kathy Sokugawa, acting director for the city Department of Planning and Permitting, said the city recently cited the United Methodist Church and its tenant for using 4548 Kilauea Ave. for “illegal bed-and-breakfast activity.” The tenant and the church were not fined for the April 5 violation because it was corrected within 30 days, Sokugawa said. The church did not return a call from the Honolulu Star-Advertiser and the tenant could not be reached.

Sokugawa said DPP has encountered “a few of these situations,” but Sofos and other real estate professionals say it’s becoming a trend.

Subleasing is generally not allowed in standard rental contracts, but it goes on, said Steve Larson, CEO, principal broker and co-founder of Koko Resorts. The next generation of subleasing has emerged with the growth of online vacation rental sites like Airbnb, HomeAway, VRBO, Expedia and Craigslist that provide more flexible and lucrative subleasing options. “I suspect that some people are using sites like Airbnb to pick out short-term roommates,” he said.

Elizabeth Churchill, owner of tourism consultancy Churchill Group LLC, said tenants sometimes have more leeway than owners, who may be bound by long-term lease requirements.

“Tenants are wily. If they can figure out a way, they will do it,” Churchill said. “My friend’s daughter does it in Venice Beach, Calif. She’s been so successful that she’s even got group business clients.”

Churchill said the practice is “brilliant,” but cautions that those who make money in the alternative accommodations industry should follow regulations and pay their share.

Sokugawa said DPP is working with the city on Resolution 17-52, which would revise ordinances to strengthen its enforcement strategy. DPP also is reviewing its civil fines policy to determine if increasing initial and daily fines for illegal vacation rental and bed-and-breakfast home activity is an option, she said.

Matt Middlebrook, Air­bnb’s public policy manager, said the company wants the city to update vacation rental laws, which don’t account for technological developments or today’s travel preferences.

Airbnb started in 2007 when two of its founders were seeking a way to “help pay rent” in San Francisco’s hot market, Middlebrook said. The company now has 3 million listings in more than 65,000 cities in 191 countries.

Airbnb officials said they have 8,400 active Hawaii hosts who are part of the more than $5 billion alternative accommodations industry in the state. Many local hosts use home sharing as a way to make ends meet, Middlebrook said.

“In Hawaii, an average host earns $11,800 per year. Hosts have told us this supplementary income enables them to keep up with the high cost of living in the islands,” he said.

The Hawaii Appleseed Center for Law and Economic Justice acknowledges that renting a property as a vacation rental may help a small percentage of struggling local families, but said their data show that the practice disproportionately benefits out-of-state interests.

“Our main issue is renting out an entire dwelling to visitors that local families could rent. When a tenant does that, it’s equally concerning,” said Gavin Thornton, Hawaii Appleseed co-executive director.