Not necessarily, sometimes fermentation can finish in as little as a few days.
This is more likely at higher temperatures. Do not exceed recommended temperatures as fast beer will come at the expense of taste. Some yeasts will ferment at different speeds at different temperatures.
Sometimes the seal between the airlock and the fermenter lid will start allowing the release of gas. To check for this simple re-adjust the airlock and see if this causes bubbling to continue. -
The airlock isn’t always the best way to determine the fermentation activity.
So, if you find that it isn't bubbling, it doesn't mean that the it isn't fermenting. If you open the lid and check for visible signs of fermentation, you should see a foam developing across the surface (called Krausen). That is an indicator that the process has started. Within 24-36 hours, carbon dioxide normally starts bubbling through the airlock, as long as everything is working correctly and if the fermenter is sealed properly.
Fermentation can take as little as 3 days if you are using a fast-acting yeast and the temperature is ideal. In cooler weather it can take up to 7-14 days or sometimes longer with bigger beers.
You need to make sure the beer is kept within the stated temperature range by the producer
(on the packet), the more stable the better! You can use a heat pad or belt to keep the temperatures up if the ambient temperature is low.
Going forward if you cannot see anything bubbling, check to make sure the seals are tightened properly and ensure you're taking your readings as well for a fully informed understanding of what is going on and when to move on to next steps. Not sure what your reading should be? Check here.