Most current wireless phone numbers can be kept when you transfer to PC mobile as your wireless service provider. For more details about bringing your number to PC mobile, or if you have any questions, please speak with a PC mobile representative at 1-877-284-6361. source
If I leave my telus account, can I use my old number and phone with you for prepaid service?
Yes. Along with your phone number, PC Mobile will transfer your existing account credit balance to your new PC mobile phone. Once you purchase a new PC mobile phone; to keep your existing number, plan and active funds, simply contact their Customer Service Centre at 1-877-284-6361 and a PC mobile representative will assist you. source