Catching a snail in Animal Crossing: New Horizons may be very easy--you Animal Crossing Bells simply need to watch for the proper weather conditions. It is among a small handful of insects and fish that have unique necessities to show up.
Snails are to be had each month at any hour of the day or night in New Horizons, but they best appear on rocks or shrubs whilst it is raining. You can trap a snail on either your own island, a chum's island, or a deserted island, so long as the wet climate situations are met and there may be a shrub or an intact rock someplace. It have to be the sort of rock you could mine with your shovel--beach boulders and the darkish rocky tide swimming pools close to your ocean don't rely, nor does discarded stone you've got dropped on the floor. Shrubs are a recent addition, made available at some point of New Horizons' first Nature Day event.
To seize a snail on a rock or shrub, just method it slowly with the net. If you run up to it or stroll too carefully by it, the snail might get scared and retract into its shell, a good way to reason it to roll off the rock and disappear. As long as it's raining, snails will ACNH Bells hold to respawn on rocks or shrubs at random, so simply hold checking round until one suggests up.