As the voyage is a quick one, there is no time to fully explore the waters of Routes 105 and 106 just yet. Return after earning the fifth Badge in order to travel at your own speed.
As you sail with Mr. Briney through Route 105, you receive a call on your PokéNav. It's Dad; he heard from Mr. Stone about you getting the device and just wanted to check in. After the brief conversation, the ship makes landfall in Dewford Town.
Dewford Town is a tiny island town in the southern ocean. Despite its isolation, many Trainers visit the area to challenge the Dewford Gym.
Located to the north of the Pokémon Center, Dewford Hall is known as "Everyone's Information Exchange". Though Dewford is a tiny island community, when someone coins a trendy phrase here, it quickly spreads throughout the region. Speak to the boy outside the building to learn the coolest thing in cool right now; if you disagree, he offers a chance to change the current phrase, which the residents inside will quickly adopt.
Hook the Big One!
Speak to the Fisherman outside the Gym, and answer his question to receive the Old Rod. This low-end fishing rod can hook Pokémon from almost any body of water, so be sure to try it out everywhere!
Dewford Town Pokémon Gym Leader: Brawly
A big wave in fighting!
The Dewford Gym specializes in Fighting-type Pokémon. Flying- and Psychic-type moves are the most useful here, so this is a great opportunity to train a Taillow, Wingull, or Ralts. Keep your Normal-, Rock-, and Dark-type Pokémon out of the fray for now. The Gym is dimly lit when you first enter, but the building lights up bit by bit for each Gym Trainer you defeat. Once the Gym Leader is defeated, the entire Gym lights up completely.
After the battle, Brawly awards you the Knuckle Badge, which ensures obedience of all Pokémon up to level 30 and enables the use of Flash in the field. He also hands out TM08 (Bulk Up) as a prize, and registers himself in your PokéNav.
Until you earn the fifth Badge, you cannot fully explore the waters of Route 106. Battle the trainers on the beach for now.
The hut on the beach's west side is known as the Seashore House, where refreshments are sold to thirsty beachgoers. Defeat all three Trainers inside, then speak to the proprietor. He rewards your effort with a free six-pack of Soda Pop! From this point on, you can also buy individual bottles at 300 apiece.
Slateport City (first visit)
Situated between Routes 109 and 110, Slateport City is by far the biggest place you've yet reached, and it is filled with sights to see. From the Battle Tent to the Oceanic Museum, there's plenty to marvel at in this seaside metropolis.
The open-air market hosts numerous vendors peddling rare goods. A man near the southern entrance hints that you'll find even more bargains after obtaining TM43 (Secret Power). Permanent stat-boosting Vitamins can be purchased from the Energy Guru. The red-clad clerk standing next to him will give your lead Pokémon an Effort Ribbon if it has been well-trained. Also after obtaining TM43, another clerk appears from whom additional copies of that and TM10 (Hidden Power) may be purchased.
In the northeast stall, a woman hands out a Powder Jar to each visitor. This jar is used to store Berry Powder obtained by playing the Berry Crush minigame in a Pokémon Center's Union Room. Collect enough powder and you can trade it to her in exchange for vitamins and herbal medicine.
Pokémon Fan Club
The Pokémon Fan Club can be found just north of the Market. If your lead Pokémon is friendly enough toward you, you can receive a Soothe Bell from the woman near the back wall. Visit with the club's chairman to have him examine your lead Pokémon's condition. If any of its five Contest stats are high enough, he will reward you with a special item—a Red, Blue, Pink, Green, or Yellow Scarf. When held, these items boost their respective stat during the Appeal Round of a Pokémon Contest.
North of the Fan Club building is the home of the Name Rater. This man has the power to evaluate and change your Pokémon's nicknames as often as you'd like. However, he cannot change a Pokémon's nickname if it first belonged to someone else.
The Slateport Battle Tent stands in the northwest corner of the city, and is one of three scattered throughout Hoenn. Each of these facilities was built to allow Trainers to experience a new way of battling. Scott is just leaving as you try to enter, and urges you to take the challenge. At this location, entrants must select three Pokémon from a random list of six rental Pokémon, all at level 30. They must then face three opposing Trainers, and after defeating each one, challengers may trade one of their Pokémon for one belonging to their opponent. No details on the opponent's Pokémon are given; challengers must instead rely on their experience battling the opponent's team. The reward for winning three consecutive battles here is a Full Heal. No experience or prize money is awarded.
The Harbor is located in the city's northeast district. Since construction is not yet complete on the new ferry, there is little to do here at the moment.
At first, it is impossible to enter the Oceanic Museum because of the Team Aqua Grunts lined up outside. But by the time you visit the shipyard, the group has made its way into the building. Pay the 50 entrance fee to follow them inside. Those that can't afford it will be mistaken as part of "the group that came in earlier", and allowed in for free.
The Grunts are more interested in the exhibits than battling with you, so speak to them in an effort to gauge their intentions. A Grunt near the entrance is shocked to see you; it's the same guy you fought back in Rusturf Tunnel! He's learned not to mess with you, and begs forgiveness with TM46 (Thief) before fleeing the scene.
Go upstairs to find Captain Stern, examining a display in the lower-right corner. Before you can hand over the Devon Goods for his new ferry, you are attacked by two Grunts! Defeat one after the other to save the captain and complete the delivery for Mr. Stone.
Trainers with a Vs. Seeker by their names, when alerted for a rematch using the item, may use higher-level Pokémon.
Shocked at their failure, the two begin to plan their next move when a stranger appears. It's their boss, Aqua LeaderArchie! He wonders aloud why you would even want to hinder their plans, but forgives you as he thinks you're too young to understand their ideals. As the group departs, he warns you against interfering with their future plans.
When you step outside, you are approached again by Scott. He seems to be a talent scout of some sort, and takes the opportunity to register himself in your PokéNav before heading off.