“I’m sure I had it in my pocket…”
“Maybe I left it somewhere…”
“My bag is missing—and so are my keys…”

For residents of rental properties, losing a key is an all-too-common scenario. While it can be stressful, the most important thing is to stay calm and follow the appropriate procedures.

This guide outlines the practical steps to take when you misplace your keys, provides an overview of the typical costs for unlocking or replacing them, and explains who is generally responsible for covering those expenses—all with clarity and precision.

What to Do First

✅ 1. Stay Calm and Search Thoroughly Within Reach

• Pockets, bags, wallets, and umbrellas

• Around the entrance—mailbox, shoe cabinet, front step

• Contact your workplace or any shops you visited

• Review your location history via smartphone photos or map apps

If you’re using a Bluetooth key finder, now is the time to activate it.

✅ 2. Contact Your Property Management Company or Landlord

If the key remains missing after a thorough search, promptly contact your building’s management company or the property owner.

Do not attempt to break the lock or replace the key independently.
Calling a locksmith without prior approval may result in disputes over cost responsibility.

If the issue occurs outside of business hours, refer to the emergency contact details provided in your lease agreement—many high-end residences offer 24/7 assistance for such situations.

✅ 3. File a Lost Property Report with the Police

If you believe the key may have been lost in a public area, it is advisable to file a formal Lost Property Report at the nearest police station or local police box.

If the key was attached to a tag containing identifiable information—such as a room number or address—a lock replacement may be required as a security precaution.

Estimated Costs When Keys Are Lost

The cost of addressing a lost key varies significantly depending on the type of lock and the nature of the response required. Below are general estimates for common scenarios (excluding tax):

Additional charges of ¥5,000 or more may apply for services rendered during nighttime or early morning hours.

Who Is Responsible for the Cost When a Key Is Lost?

In principle, the cost of unlocking or replacing a lost key is considered the tenant’s responsibility, as it typically results from tenant negligence. Therefore, the tenant is generally expected to bear the full cost of the response.

However, there are notable exceptions:

◯ Coverage Through Fire Insurance or Tenant Support Services

Some fire insurance policies or tenant assistance programs include “key loss and lockout support”.
In such cases, the cost of unlocking or even full reimbursement for key replacement may be covered. It is highly advisable to review your policy’s benefits in advance.

◯ Discounted Services Through Property Management

In select properties, management companies may offer access to preferred locksmiths at reduced rates. Additionally, some residences provide a spare key lending service, which may be available upon presentation of identification and your lease agreement.

Important Considerations When Unlocking or Replacing a Key

• You must be present during the unlocking process to verify your identity

• Never attempt to forcibly enter the property by breaking the door or lock

• Key replacement should be undertaken if there is a risk that someone else may possess the original key.

→ For example, if the key was lost along with documents displaying your address, a full lock replacement is highly recommended for security reasons.

Preventive Measures: Minimizing the Risk of Future

• Leave a spare key with a trusted family member or friend

• Avoid making duplicate keys at locksmiths without authorization—consult your property management to request an official copy

• Reevaluate how you carry your key—consider using a discreet key holder or an inner pocket within your bag

• Consider smart lock systems or Bluetooth-enabled key finders for added convenience and security

Final Note: Remain Calm, Act Quickly, and Follow Proper Procedures

Losing your key is neither uncommon nor something to be embarrassed about. What matters is responding calmly and responsibly—starting with notifying your property manager.

While some costs may be unavoidable, unauthorized actions such as forcing entry, replacing the lock without permission, or ignoring the issue can lead to far more serious complications.

By preparing a simple action plan in advance—what to do if your key is lost—you’ll be equipped to handle the situation confidently, maintaining peace of mind in your refined and secure living environment.