Most leases prohibit subletting, or only allow it with permission. OP • 10mo ago •.Subletting without landlords approval unless stated in the lease is absolutely illegal. As per California law, leases can indeed require tenants to obtain permission from their landlords before subletting the rental property. Subletting a rental is permitted in California if the landlord doesn't expressly prohibit it in the lease agreement. 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. Tenants generally can't sublet their unit without the landlord's consent. Protect your rentals with Avail lease agreements and amendments. California law requires tenants to seek explicit, written permission from their landlords to sublet if it is not already allowed in the lease. According to California law, tenants must get their landlord's written permission before subletting their apartment.