How do I get a trust account number for a new trust or estate, and is the T3APP still the way to do it?
Form T3APP is the CRA's application for a trust account number, a T followed by eight digits that every T3 return needs. The trustee or executor gets it instantly through Trust account registration in a CRA portal, or mails a signed T3APP with a copy of the will or trust document. Mailed forms carry no published processing time.
Online or by mail: which route gets your client a number?
A trust needs a trust account number to file a T3 return, and the trustee can get one through the online Trust account registration service or by completing Form T3APP canada.ca. The online service sits in My Account, My Business Account and Represent a Client
canada.ca. The number is a T followed by eight digits
canada.ca.
| Online (Trust account registration) | Paper (Form T3APP) | |
|---|---|---|
| Where | My Account, My Business Account or Represent a Client | Winnipeg or Sudbury Tax Centre, by mail |
| When the number arrives | On screen at the end of the registration | By mail after the CRA processes the form |
| Trust document or will | Upload it, or send a copy to the CRA | Attach a copy to the T3APP |
| Current version | Online service | T3APP E (25) |
The CRA's own form says it plainly: register online to receive the number instantly canada.ca. After an online registration, the number shows on screen and you still submit a signed copy of the trust document or will; a mailed T3APP gets its answer by post once processed
canada.ca. As of October 2026, the CRA publishes no processing time for a mailed T3APP, so paper only makes sense when nobody can sign in.
What does the CRA need from an estate versus an inter vivos trust?
Every application needs the trust's name, the trustee's contact details, the trust type and a signed copy of the trust document or the deceased's signed will canada.ca. An estate created on death is a testamentary trust; any trust that is not testamentary is an inter vivos trust
canada.ca. The extras differ.
| Item | Estate (testamentary trust) | Inter vivos trust |
|---|---|---|
| Core document | Signed will, or a court order under provincial or territorial law | Trust agreement, deed or declaration |
| Date the form asks for | Date of death | Date the trust was created |
| Extra identifier | Social insurance number of the deceased | None |
| If a named executor died | Copy of their death certificate | Not applicable |
| If a named executor will not act | Their letter of renunciation | Not applicable |
| No written document | Not applicable | A written summary titled "Summary of [trust name]" |
The date of death and the deceased's SIN come from Step 4 of the T3APP, which also describes a testamentary trust as one set up by a will or by a court order under provincial or territorial law canada.ca. The death certificate and renunciation letter come from the CRA's list of what to have ready
canada.ca. The written summary option for a trust with no document is in the T3 guide
canada.ca.
Where does a paper T3APP go?
The mailing address depends on the trustee's address, not the trust's assets canada.ca.
| Trustee's mailing address | Send the T3APP and documents to |
|---|---|
| Alberta, British Columbia, Manitoba, Saskatchewan, Northwest Territories, Nunavut, Yukon | Winnipeg Tax Centre, Post Office Box 14000, Station Main, Winnipeg MB R3C 3M2 |
| Hamilton, Kitchener and Waterloo areas of Ontario; Montreal and Sherbrooke areas of Quebec | Winnipeg Tax Centre |
| Outside Canada, or the trustee is a deemed resident | Winnipeg Tax Centre |
| Anywhere else in Canada | Sudbury Tax Centre, Post Office Box 20000, Station A, Sudbury ON P3A 5C1 |
Send the T3APP on its own. The T3 guide says not to send Form T3APP with the T3 return canada.ca. For status questions, the trust line is 1 800 959 8281 within Canada and the continental United States, or 613 940 8495 collect from elsewhere
canada.ca.
How an estate gets its number: a worked example
Your client's mother died March 3, 2026, and your client is executor under the will. The estate earns interest and sells a rental property after death, so it has to file a T3: an estate generally files when it realizes a gain or receives payments after the death canada.ca.
Your client signs in, opens Trust account registration, and enters the estate's name, the executor's contact details, the date the estate began and its trust type. The number appears on screen at the end. Your client then uploads the signed will with the Submit trust documentation button on the last page, or sends a copy to the CRA canada.ca.
Say the estate keeps a December 31 year end. Its first T3 then covers March 4 to December 31, 2026 and is due March 31, 2027, 90 days after year end. A graduated rate estate can pick a different year end; the T3 filing deadline page counts the days for each one, and the T3 return for an estate covers what goes on it.
The penalty arithmetic is why you write the number down at once. The T3 guide sets a $100 penalty for each failure to show the number on a T3 return, trust slip or trust correspondence canada.ca. A return and three beneficiary slips filed without it are four failures, up to $400. A T3 adjustment request has to quote the number too.
What stalls a first T3 return?
The common one is waiting too long to apply. A trust needs the number to file electronically, and a trust filing for the first time has to request it before it files canada.ca. With the online service handing it over on screen, there is no reason to leave it until March.
The second is the missing document. The form's own Step 5 says you must send a copy of the trust document or will with the T3APP canada.ca. If it never reached the CRA, the first T3 has to include it, along with a list of assets held at the date of death for a testamentary trust
canada.ca.
The third is access. My Trust Account opens only through Represent a Client, and the primary trustee has to register for it first before adding anyone else canada.ca. For offline access, the trustee attaches Form AUT-01 to the paper T3APP; that representative can't change the address, direct deposit, other representatives or a debit agreement
canada.ca.
Not every estate or trust needs a number
The number exists to file a T3. An estate distributed immediately after the death, or one that earned no income before distribution, may not need to file at all; give each beneficiary a statement of their share instead canada.ca. The deceased's final T1 is still due either way
canada.ca, see the final return.
Bare trusts are outside the trust reporting rules for taxation years ending on or after December 31, 2024 and before December 31, 2026, so as of October 2026 they don't file for 2025 canada.ca. The 2026 position is on bare trust filing requirements. A nonresident trust electing to file under section 216 uses the same T3APP
canada.ca.
Sources
Can I paper file the first T3 and let the CRA assign the number?
Don't plan on it. The T3 guide says a trust filing for the first time has to request a trust account number before it files, and electronic filing needs one canada.ca. Register online and the number shows on screen at the end of the registration.
Does a second executor need to sign the T3APP?
No. The primary trustee in Step 2 certifies the form, and any other trustees named in the will or trust document are given authorization to deal with the CRA on the trust's behalf canada.ca.
Does the trust get a new number if it stops being resident in Canada?
No. The trust keeps the same account number even when its residency status changes canada.ca.
How do I find a number the trustee has lost?
Online, a trustee registered in My Trust Account can see it there; otherwise send a written request to the tax centre listed on page 3 of the T3APP, or phone the CRA canada.ca.
General information for the tax year shown, not advice for a specific client. Confirm the facts before you file or remit.