Yes, in almost every case. Losing your number is one of the most common (and most avoidable) fears business owners have about switching.
Answer: The process is called number porting, and it's a standard part of switching telecom providers. Your new provider handles the request with your old carrier, and your number transfers over on a scheduled date, typically without any service gap if it's planned correctly. The only numbers that occasionally can't be ported are certain toll free or specialty numbers, and even those usually have a workaround. Always confirm porting timelines in writing before you cancel anything with your old provider.