Route 123 begins in the north on a long pier leading from Route 122. However, fishing along the pier is blocked by stone barriers. At the end of the pier, the route curves to the west. East of this spot, a single cuttable tree blocks access to a pair of paths through the forest. The north path leads to a Trainer, Psychic Cameron. The south path leads to a Rare Candy in Ruby and Sapphire Versions, or to a Double Battle in Pokémon Emerald.
West of the soil patch, Route 123 meets the first of two shortcut paths in the area, blocked by a tree. By removing this tree, Trainers can avoid a large patch of tall grass on the main path. To the west of the grass, the two paths reunite near a second tree. Removing this tree also allows Trainers to avoid walking through grass to reach another soft soil patch with two Leppa plants. Otherwise, a northerly trek from the main path, past a Trainer, and through tall grass is necessary to reach the plants.
From this point westward to the section of the route accessible from Route 118, Route 123 is divided by the terrain into a northern path and a southern path. It is possible here to go from the northern path to the southern path via ledges, but not vice versa.
Rain occurs one out of every four days on this route; each time it rains on Route 123, Route 119 experiences thundery downpours at the same time.
From the start of the path near the Leppa plants, 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 (where a grassy corridor leads to the southern path) before returning to the north and forcing travelers into the path of a well-placed Trainer. From here, the path turns west, hopping down a ledge into a grassy area before going over yet another ledge. Here, the path runs south of a small pond. To the left of the pond is a Calcium. Southwest of the item, the northern path crosses over its final ledge and merges with the southern path.
From the Trainer south of the Leppa Berries, the route heads west over a ledge and comes to a fork in the road. The south fork leads the southern path down a ledge while the north fork is a grassy corridor that connects to the northern path. Following the south fork, the path goes over the aforementioned ledge, passes through an empty area, and hops down another ledge to run into the path of Psychic Jacki (who can be bypassed by walking south of the rock, along the treeline). To Jacki's west is a final ledge, as well as a pair of Twins who will partake in a Double Battle. West of the twins, the northern and southern paths merge into a single route 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.
To the west of the Berry Master's house is the western terminus, where Route 123 becomes Route 118.
Berry Master's house and garden
Inside, the Berry Master gives out two Berries each day. His wife gives out extremely rare Berries if she is told one of a number of special phrases. In Pokémon Omega Ruby and Alpha Sapphire, the man next to the Berry Master will give the player a Gracidea flower if they have a Shaymin in their party.
Outside, there are soft soil patches for Berries to grow in. In Pokémon Ruby, Sapphire, and Emerald, there are six plots with two spots each, allowing for 12 different Berry plants to be grown. In Pokémon Omega Ruby and Alpha Sapphire, there are four plots with six spots each, allowing for 24 different Berry plants to be grown.
The Berry Master's wife asks the player about good sayings once per day. She rewards the player with a rare Berry when she is told about each of five special phrases, but will only give a rare Berry once for each special phrase.
In Pokémon Ruby, Sapphire, and Emerald, the player tells her a two-word phrase once per day using the easy chat system. If the player tells her one of five special phrases, they are given one of five rare Berries. Four of the phrases contain one unlockable word: the player cannot say CONTEST or SUPER until they have entered the Hall of Fame, and the player cannot say LATIOS or LATIAS until they have seen that Pokémon. If the player tells her any other phrase or any phrase that she has been told before, she will give the player a random Berry from among the first ten (Cheri Berry to Sitrus Berry).
In Pokémon Omega Ruby and Alpha Sapphire, the Berry Master's wife prompts the player with half of the phrase, replacing one of the words with SOMETHING. The player is required to tell her only the missing word (not the whole phrase) using free text entry with a 16-character limit; this entry is case sensitive, so the player must enter the word in all capital letters. If the player tells her anything other than the prompted word, she will give the player a random Berry from among the first ten (Cheri Berry to Sitrus Berry). After the player has told her all five special phrases, she gives the player a random Berry from among the first ten without asking for a special phrase at all.
In Pokémon Omega Ruby and Alpha Sapphire, Aroma Lady Violet and Twins Miu and Yuki can be fought earlier than the other Trainers on Route 123 by accessing it via Route 118. At levels 36 and 38, however, their Pokémon are much stronger than the nearby Trainer Pokémon in Route 118, whose levels range between 26 and 29.
The levels of their Pokémon are even higher than those belonging to Winona, the next Gym Leader, whose strongest Pokémon is a level 35 Altaria. This is the only instance in the Pokémon Omega Ruby and Alpha Sapphire games where a Trainer can be battled before a Gym Leader and use higher leveled Pokémon.
Route 123, along with Route 122, has the same music as the introduction cutscene at the start of the Hoenn games.