No, once you port away your number, Twilio no longer has control over the phone number. It will be up to your new carrier to provide voice and/or SMS services. It is also the responsibility of your new carrier to ensure the proper execution of the port. Once Twilio confirms that the port-out has been completed, the phone number will be removed from your account after a short period of time.
However, Twilio may still be able to provide messaging services via Hosted SMS for some phone numbers, even after they have been ported away. For full details, including how to request this service, please refer to our Hosted Numbers FAQ. This option allows you to maintain messaging capabilities with Twilio while your voice services are managed by another provider.