• The Fundamental Difference

When you sublet, you temporarily transfer possession of your unit to another person (the subtenant) while remaining the named tenant on the original lease. Your name stays on the agreement with your landlord. You are responsible for ensuring rent is paid — even if the subtenant is the one actually paying — and you are liable for any damage they cause to the unit. The subtenant's agreement is with you, not directly with the landlord. When the sublet period ends, you have the right to return to the unit.

When you assign, you transfer all of your rights and obligations under the lease to another person (the assignee). Once the assignment is complete, you are generally no longer a party to the lease — the assignee steps into your position and deals directly with the landlord for the remainder of the lease term. You typically have no right to return to the unit. An assignment is the appropriate mechanism when you need a permanent exit from a lease that has not yet expired.

• When Each Option Makes Sense

A sublet is appropriate when your departure is temporary. A four-month work contract in a different city, an extended trip, a trial period living with a partner before formally moving — these are situations where you expect to return and want to preserve your tenancy. The sublet lets you cover your rent obligations during the absence without permanently giving up the unit.

An assignment is appropriate when you are leaving for good and do not intend to return before the lease expires. A job relocation, a purchase of a home, a move to a larger unit — situations where the departure is permanent and you need someone else to absorb the remaining lease term. If you are certain you will not return, a sublet creates unnecessary ongoing liability. An assignment cleanly ends your obligations on the assignment date, provided it is properly executed and consented to.

• Landlord Consent: The Rules Across Canada

In most Canadian provinces, a tenant must obtain the landlord's consent before subletting or assigning. However, this consent requirement comes with an important legal limitation: a landlord generally cannot unreasonably withhold consent for either a sublet or an assignment. This protection is codified in tenancy legislation in Ontario, British Columbia, and other provinces, and it is meaningful.

In Ontario, the Residential Tenancies Act explicitly states that a landlord shall not arbitrarily or unreasonably withhold consent to an assignment. If a landlord refuses consent without a valid reason, the tenant may apply to the Landlord and Tenant Board, which can authorize the sublet or assignment over the landlord's objection, or allow the tenant to terminate the tenancy early. In BC, similar protections exist under the Residential Tenancy Act. The process for obtaining consent typically involves submitting a written request to the landlord with relevant information about the proposed subtenant or assignee.

• What “Unreasonable Refusal” Means Legally

Not every refusal is unreasonable. A landlord can legitimately refuse consent if the proposed subtenant or assignee does not meet the same criteria used to screen tenants generally — inadequate income, poor credit history, or a prior eviction for cause. A landlord can also refuse if the proposed use of the unit would violate the lease (for example, if a commercial subtenant is proposed for a residential tenancy).

What landlords cannot do is refuse simply because they want to choose their own tenant, because they want to take the opportunity to raise the rent, or because they dislike the arrangement in principle. Refusal motivated by a desire to terminate the tenancy or re-let at a higher rate is generally considered unreasonable under Canadian tenancy law. If your landlord refuses without articulating a legitimate reason related to the specific proposed tenant, that refusal may be challengeable at the provincial tenancy tribunal.

• Finding and Vetting a Subtenant or Assignee

The quality of the person you bring in matters both legally and practically. For a sublet, you remain liable if they default, so your due diligence protects you financially. For an assignment, a well-qualified assignee reduces the chance of landlord refusal. In both cases, apply the same screening criteria a landlord would use: income verification (typically employment letter, recent pay stubs, or T4), a credit check (with the applicant's written consent), and reference checks from previous landlords.

Finding candidates follows the same channels as renting generally: online listing platforms, workplace bulletin boards, community groups, and personal networks. Be clear in any listing about the nature of the arrangement — sublet with a defined end date, or assignment for the remainder of the lease — to attract candidates whose needs align with what you are offering. Mismatched expectations between the tenant and subtenant are a frequent source of disputes.

• Condo-Specific Restrictions

If your rental unit is a condominium, there is an additional layer of rules that may apply beyond the provincial tenancy legislation. Many condominium corporations have bylaws that restrict or prohibit short-term rentals, regulate the minimum rental period, or require approval of a tenant by the condo board before occupancy. These condo rules are separate from and in addition to the tenancy rules between landlord and tenant.

Your landlord (the condo unit owner) may be unable to consent to a sublet even if they wanted to, because the condo corporation's declaration prohibits it. Before proceeding with any sublet or assignment in a condo unit, ask your landlord directly whether the condominium's rules permit it and whether any board approval is required. Proceeding without complying with condo rules can result in the corporation taking action against the unit owner, which can in turn affect your tenancy.

• Damage Liability: Who Pays?

In a sublet, the original tenant remains the landlord's counterparty. This means that if the subtenant damages the unit, the landlord's claim is against you — not the subtenant. You would then need to pursue the subtenant separately under your own sublease agreement. This is one of the most significant practical risks of subletting: you are underwriting the subtenant's behaviour to your landlord, even though you are not present in the unit.

In an assignment, once the assignment is properly completed and consented to, the assignee takes on the obligations of the lease — including responsibility for damage. The landlord's claim for damage goes to the assignee. Your exposure ends on the assignment date. This clean transfer of liability is part of what makes assignment the preferable mechanism for permanent departures, provided you have properly documented the handoff and the landlord has consented in writing.

• Sublet vs. Assignment: Side by Side

The table below compares sublet and assignment across six key dimensions to help clarify which option is appropriate for a given situation.

• Get It in Writing: What Your Agreement Should Cover

Whether you are subletting or assigning, a written agreement is not optional — it is what protects you when something goes wrong. The agreement does not need to be complex, but it must cover the essentials clearly.

For a sublet agreement, document the full names and contact information of both the original tenant (sublandlord) and the subtenant, the address of the unit, the sublet start and end dates, the monthly rent to be paid by the subtenant and the method of payment, a reference to the original lease (attach a copy), a statement of the unit's condition at the start of the sublet with supporting photos, the rules the subtenant agrees to follow (use and care of the unit, noise, guests, pets if applicable), and the consequences if the subtenant defaults on rent or causes damage. Include a clause stating that the subtenant has read and agrees to comply with the original lease terms.

For an assignment agreement, the document should state clearly that the original tenant is transferring all rights and obligations under the lease to the assignee effective on a specific date, that the assignee accepts those rights and obligations, and that the landlord has consented. Include the landlord's written consent (or reference the consent letter), the assignment date, a condition report for the unit at the time of handoff with photos, and a statement that the original tenant has no further obligations under the lease from the assignment date forward. Both the original tenant, the assignee, and the landlord should sign and receive copies.

• Know Which Option You Actually Need

The question to ask yourself is straightforward: are you leaving temporarily or permanently? If temporarily, a sublet lets you preserve the tenancy and return. If permanently, an assignment exits you cleanly. Either way, the landlord's consent is required but cannot be unreasonably withheld — and if it is unreasonably withheld, you have a legal remedy. The process is more manageable than most tenants expect once you understand the distinction, screen your candidate properly, and document everything in writing from the first conversation to the final key handover.