Never have done this myself (but will be next year), so I looked this up for you on TripAdvisor. Sample letter included at the bottom.
Travelling with Children
If a child is traveling with one parent, the border services official may require a letter of permission from the other parent or documentation that demonstrates that the lone parent is the child's sole guardian. If a child is traveling with someone other than his or her guardian, border authorities will want to see a letter of permission from both of the child's parents / guardians. Ideally, the letter should be notarized. You can use this sample letter of consent as a starting point.
Note: It is strongly recommended that children travelling alone or with one parent carry a consent letter for each and every trip abroad. Although anyone can witness/sign these letters, it is advisable to have the consent letter certified, stamped or sealed by an official who has the authority to administer an oath or solemn declaration (i.e., a commissioner for oaths, notary public, lawyer, etc.) so that the validity of the letter will not be questioned. It is up to each official/individual who witnesses such a letter to decide what proof he/she needs to see to be able to witness/sign the letter. Officials should only witness/sign a letter of consent if he/she is convinced that the individual requesting the letter is who he/she claims to be and that adequate proof has been provided.
This consent letter may be required by foreign authorities among other additional country-specific entry requirements. You should contact the representatives of the country or countries to be visited by the child to ensure that you have the most up-to-date information regarding their specific entry requirements as permission to enter another country is the sole prerogative of that country.
We also strongly recommend that you contact the transportation company (airline, train, bus, etc.) in order to observe any additional policies that they might have in place.
Further information is available in the FAQ and Children and Travel sections.
The following sample letter can be amended to meet your specific situation and requirements.
To Whom It May Concern
I (We), ________________ (full name(s) of custodial and/or non-custodial parent(s)/legal guardian(s)), am (are) the____________________ (lawful custodial parent and/or non-custodial parent(s) or legal guardian(s))
of
Childs full name: _____________________________________
Date of birth (DD/MM/YY): _____________________________
Place of birth: ________________________________________
Canadian passport number:_____________________________
Date of issuance of Canadian passport (DD/MM/YY): ________
Place of issuance of Canadian passport: __________________
________________ (childs full name), has my (our) consent to travel with
Full name of accompanying person: _______________________
Canadian or foreign passport number: _____________________
Date of issuance of passport (DD/MM/YY):_________________
Place of issuance of passport: ___________________________
to visit ______________ (name of foreign country) during the period of __________________ (dates of travel: departure and return). During that period, ________________ (childs full name) will be residing with ________________ (name of person where child will be residing in foreign country) at the following address:
Number/street address and apartment number: ______________
City, province/state, country: _____________________________
Telephone and fax numbers (work and residence): _______________________
Any questions regarding this consent letter can be directed to the undersigned at:
Number/street address and apartment number: ______________
City, province/state, country: _____________________________
Telephone and fax numbers (work and residence): _______________________
Signature(s):______________________________________ Date:_________________
(Full name(s) and signature(s) of custodial parent,
and/or non-custodial parent(s) or legal guardian(s))
Signed before me, ________________ (name of witness), this _________________ (date) at ________ ______ (name of location).
Signature: ________________ (name of witness)
