Dozens of nonprofit organizations have made plans in recent months to leave downtown Oakland as commercial rents skyrocket, changing not just the neighborhood landscape, but where low-income children and families go to get basic services.

Many of the nonprofits signed leases when building vacancies were high and the local economy was climbing out from the depths of the recession. With their agreements now expiring, organizations are seeing their rents nearly double.

Some have chosen not to renew and move instead, while several have downsized in response. Others, still, have little say in the matter as buildings change hands to developers that do not offer renewal deals.

Most have tried to stay in the city and resettle in places like East Oakland or near the airport, where commercial rents have remained relatively steady, but a few have left the city for Alameda, Emeryville and other surrounding locales.

“Having to search for a new space in this super-tough rental market has been a huge time suck,” said Holly Joshi, executive director of Misssey, a nonprofit that helps sexually exploited youth and works closely with the Alameda County district attorney’s office. The organization’s lease for its space at 14th Street and Broadway is up June 30, and Joshi said the rent increase quoted to her means that “we’re absolutely leaving.”

The Eviction Defense Center, a nonprofit located two blocks away, has a lease that’s up in the fall, and it’s preparing to move, too, as it anticipates a steep rent hike. So is the nearby Oakland Private Industry Council, which has a contract with the city.

Other nonprofits — including the antibullying group Not In Our Town, Bay Area Girls Rock Camp, East Bay Alliance for a Sustainable Economy and the Oakland branch of the International Rescue Committee — have already relocated. The rescue group, which assists refugees, asylum seekers, victims of human trafficking and survivors of torture, moved from San Francisco to downtown Oakland about three years ago as the market there boomed, before needing to pack up again last year for the same reason. It’s now just north of Lake Merritt.

Real estate agent Alex Epstein said that of the 37 downtown Oakland nonprofits he has represented since the start of last year, 30 have been unable to afford a fair market value renewal for their existing office.

“Oakland has always been waiting for the next wave to come to it. Ten years ago it was biotech, which of course never came. Fifteen years ago it was the so-called multimedia boom,” said Karen Chapple, a UC Berkeley professor of city and regional planning and leading expert on urban displacement. “Now there’s the hope that the technology boom will spill over from San Francisco, partly because the workers have already relocated to Oakland. It looks like some of that spillover has materialized in this go-around.”

Factors contributing to the tough market are the absence of commercial development, an exceptionally low vacancy rate — less than 5 percent for office spaces — plus the impending arrival of Uber and the sale of older buildings to developers that refurbish the properties and increase their value.

But the downtown churn — similar to San Francisco’s loss of nonprofits over the past decade — has happened even as the overall number of jobs in Oakland’s nonprofit sector has climbed over the past six years, city records show. Growth has been driven in part by organizations moving in from San Francisco, such as the Sierra Club, or from places such as Berkeley, such as the Greenlining Institute.

“When you’re talking about city intervention or assistance, we don’t want to be casting a wide net,” said Marisa Raya, a city analyst who researched the issue for an informational report this year. “We want to be specific about identifying organizations that have been in Oakland a long time.”

The nonprofits impacted most by displacement forces are those that cater to minorities and low-income populations, Raya said, because they have trouble getting access to capital, such as bank loans.

City officials and foundations that fund nonprofits are encouraging the groups to share space with each other, purchase buildings or try to secure long-term leases. But many groups say those remedies are not feasible, based on their budgets or the type of services they provide.

Nonprofit leaders say the downtown corridor along Telegraph Avenue and Broadway, between the downtown BART stations, is optimal for the work they do because it’s accessible by public transportation and close to city and county buildings to which they can refer clients. For nonprofits that serve youth from warring neighborhoods, downtown is one of the few communal places for them to come together.

“If you want a neutral area where all kids feel safe, where they don’t have a territory on their back, you have it in a central area,” said Nyeisha DeWitt, founder of Oakland Natives Give Back, which fights chronic absenteeism in schools. “That’s what downtown is, not just for kids but for their families. Parents have the same generational baggage and the same implications.”

DeWitt’s nonprofit is moving in a few weeks from its 17th Street location near Telegraph Avenue to the Pill Hill neighborhood. It will share a space there with the Hidden Genius Project, a nonprofit also facing displacement, which teaches computer science and entrepreneurial skills to male African American teenagers.

“We’ll just make it a home, hopefully with plans to be here for the long haul,” DeWitt said of the new location. “When you’re a nonprofit and you’re trying to show stability and consistency to the people you serve and the people who fund you, moving all the time doesn’t look good.”

Kimberly Veklerov is a San Francisco Chronicle staff writer. Email: kveklerov@sfchronicle.com Twitter: @kveklerov