What's the best way to get from Vancouver to Victoria?

Ferry is the more practical and popular way. https://www.bcferries.com/routes-fares/schedules/daily/TSA-SWB

Flying is the alternative. One option--https://www.harbourair.com/

The ferry is fun

Make your bus / ferry booking here for pickup at the Sutton Place Hotel

https://gowilsonsgroup.betterez.com/cart/5d640e6c3508c612050003bc/reservation/5dcdadb67151001a3a62e3ab

Taking a helicopter or a floatplane harbour to harbour is an option at 3 x the price of the bus / ferry option. Caution on the flying options, weather can be an issue and flights can be cancelled. If that happens and you can't get a bus reservation THEN you're scrambling to get a last minute flight out of YVR to YYJ at that same 3 x the price. Just saying.

But if you do go the flying route, i'd take the floats over the chopper, everytime.

Ferry. I love ferries and this particular one is very nice and scenic.

Helijet is fun-er.

helijet.com

I took a whale watching boat there and the seaplane (see Joe’s link) back. Lots of fun for another landlocked traveler!

Here is the website for the ferries.
https://www.bcferries.com/

You absolutely need to make a reservation if you have a car, just to guarantee a spot on board....no need for one if you will be on foot.
The ferry between Vancouver and Victoria takes a very lovely scenic route through the islands in between.
You want the Tsawwassen to Swartz Bay route.
If you're on foot, there is a city bus at Swartz Bay Terminal to take you into downtown Victoria.
Very easy!

Thanks everyone for all your help. I booked the ferry and looking forward to being on the water!