It depends on the bus company. Some companies may offer a few minutes of tolerance after the boarding time, but this is not guaranteed, and not all follow this practice. Many companies prefer to stick to the scheduled time.

So, the best advice is to not take risks and arrive early. However, if you realize you might not make it on time, try contacting the bus company to see if they can wait for you a little longer. If it's not possible, you can check directly with the company to see if it's possible to reschedule your ticket. Each bus company has its own rules for these situations.