If our home country doesn't have a *reciprocal licence exchange agreement with Ontario, we cannot Swap our current D/License to get a Toronto D/License.
*Reciprocal License Exchange Agreement exists between Ontario and: US, Japan, Korea, Switzerland, Germany, France, UK, Austria & Belgium.
But, in that case do we have to START all over Again? No...
We can immediately apply & get a Toronto (Ontario) Driving License thru the following procedure:
1. Before we land, we must obtain a 'Letter of Authentication' (in English) from the home country's Roads & Transport Authority, stating "more than 24 months" driving experience in our country.
2. Take also a 'True Translation Copy' (in English) of our D/License from Road & Transport Authority.
3. Both of the above, in most cases, would be clubbed in one letter.
4. Or obtain an International Driving License* (IDL / IDP).
*This is nothing but a translated copy of our present d/license. (it can be used in lieu of the item stated in point-2 above).
With the foregoing, we can drive a car abroad for three  months (2 months, in Ontario). Within that time apply for the Ontario Driving License. The procedure of which is given at:http://www.drivetest.ca/en/license/OutOfCountry... the salient points of which I am listing below.
In such cases we are called 'Out of Country Drivers' and we can skip the G1 'waiting period' and get a G2 driving license [provided we have the above 24 Months letter]:
(a) Now for the Ontario driver's licence are required to;
-a1. present a valid foreign driver's licence (if it is not in English or French, it is to be accompanied by a written translation from a qualified translator); [we got that, as above]
-a.2: pass a vision test and a written knowledge test regarding Ontario's traffic rules;
-a.3: pay all applicable fees;
-a.4: Provide acceptable proof of identity.
(b) Applicants are required to provide adequate proof of foreign driving experience. (However, if it is not there, the ministry will accept applicants' declaration of their foreign driving experience on the driver's licence application for up to a maximum of 12 months experience. In that case we get the G1* license only.
Based on the 24 months Authentication Letter the ministry will recognize the applicant's foreign driving experience as certified on the authentication letter AND,
(a) We can attempt the G2**Exit Road Tests (mandatory wait times are waived).
(b) Upon successfully passing the G2 Exit Road Test, we get the G2 license.
(c) After few months of driving under G2 we can apply for a G***Licence.
(d) If applicants do not provide a letter of authentication, applicants must pass the G1 road test and must fulfill the 12-month waiting period prior to taking G2 road test.
*G1 licence has certain limitations like we have to always drive alongwith a G license holder. It is thus, useless for us, who have good & adequate driving experience under similar driving conditions & system as that of Canada [read 'left-hand drive' experience & similar road/traffic management conditions].
**G2 license is as good as G, except that we cannot drive on the Highway at certain times (Midnight Rush Hrs. when truck movement starts).
***G License is the 'full fledged' driving license.
Ps.: The procedure is pretty much similar with all other provinces.