You can, but it's not a good idea. Most leases prohibit subletting, or only allow it with permission.Subletting a rental is permitted in California if the landlord doesn't expressly prohibit it in the lease agreement. Subletting without landlords approval unless stated in the lease is absolutely illegal. According to California law, tenants must get their landlord's written permission before subletting their apartment. If you have a lease for a set term, like one year, you can sublet with or without your landlord's permission, unless they prohibit this in the written lease. There is no way in California to legally sublet without the express permission of your landlord. There are six major steps in the process of subletting legally. Learn how subletting and roommate replacement affect the rights and responsibilities of landlords and tenants under the Berkeley Rent Stabilization Ordinance. So the answer to your question is no; CA law doesn't require a co-tenant to have permission to sublease.