Understanding California Law: Subletting Prohibited. California law prohibits subletting without landlord consent.You can, but it's not a good idea. Most leases prohibit subletting, or only allow it with permission. Subletting without landlords approval unless stated in the lease is absolutely illegal. Subletting a rental is permitted in California if the landlord doesn't expressly prohibit it in the lease agreement. 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. California law requires tenants to seek explicit, written permission from their landlords to sublet if it is not already allowed in the lease. So the answer to your question is no; CA law doesn't require a co-tenant to have permission to sublease.