The route begins on a long pier leading from Route 122. However, fishing along this stretch is hindered by the presence of stone barriers around the water. At the end of the pier, Route 123 curves to the west. East of this spot, a single Cut-able tree blocks access to a pair of paths through the forest. The north path leads to a trainer, Psychic Cameron. The southern path leads to a Rare Candy in Ruby and Sapphire, or to a double battle in Emerald.
Back on the main path, Route 123 passes by a loamy soil patch containing three varieties of Berries. To the left of the soil is a girl who loves Template:Type2 Pokémon. If trainers speak to her while carrying a Grass-type in their party, she will present the trainer with TM19 (Giga Drain).
West of the soil patch, Route 123 meets the first of two shortcut paths in the area blocked by a tree. By removing the first tree, trainers can avoid a large patch of grass on the main path. To the west of the grass, the two paths reunite near the second tree. By removing this tree, trainers can avoid walking through grass to reach a loamy soil patch with two Leppa Berry plants. Otherwise, a northerly trek from the main path past a trainer and through grass is necessary to reach the plants.
From this point westward to the segment of the route accessible by Route 118, Route 123 is divided by the terrain into a northern segment and a southern segment. It is possible at almost any time to go from the northern segment to the southern segment via ledges, but not vice versa.
Northern segment
From the start of the segment near the Leppa Berries, the path hops down a ledge, passing an Elixir before entering a patch of grass. At the west edge of the grass, the path turns south, hopping down two more ledges (with a grass-lined path to the southern segment in between) before returning to the north and leading trainers into the path of a well-placed trainer. From here, the segment turns west, hopping down another ledge into a grassy area before jumping down yet another ledge. Here, the segment passes to the south of a small pond. To the left of the pond is a Calcium. Southwest of the item, the northern segment crosses over its final ledge, merging with the southern segment at this point.
Southern segment
From the trainer south of the Leppa Berries, the route heads west over a ledge before coming to an awkward fork in the road. The south fork leads the southern segment over a ledge while the north fork leads to a grass-filled corridor that eventually comes out on the northern segment. By following the south fork, the path hops over the aforementioned ledge before passing through an empty area and hopping another ledge to run into the path of Psychic Jacki (who can be bypassed by walking south of the rock, along the treeline). To her west is another ledge, the final one on the segment, as well as Twins who will partake in a double battle. West of the two trainers, the two segments of the route merge into a single Route 123 once again.
Just west of the merge point, there is a hole in the fence that lines the southern portion of the route in this area, leading to an Ultra Ball.
Farther west, the route passes by the Berry Master's house. Inside, the Berry Master will give out two Berries each day. His wife will give out extremely rare Berries if she is told one of a number of special phrases. Outside, there are six loamy soil patches with two spots each, allowing for 12 different Berry types to be planted.
To the east of the Berry Master's house, Route 123 becomes Route 118.
In Pokémon Emerald, two trainers were added to the area south of the six loamy soil patches. Also, a trainer was added in the area east of Jacki, as well as to the area south of the Leppa Berries.
