In Generation II, while there are no Trainers other than Jasmine in Olivine Gym, the lighthouse poses a challenge which provides more than enough of a counterbalance to it, as there are many Trainers on each of its floors.
In HeartGold and SoulSilver, Gentleman Preston and Lass Connie are actually Trainers from the Gym, and will return there once Amphy has been cured. Also in Generation IV, once the player has spoken to her, Jasmine opens a door leading to an elevator that goes from the top floor directly back to the bottom. Due to the addition of an elevator, the Lighthouse was redesigned so that the ground floor was a tourist deck, and no Trainer can be found training until the upper floors are reached.
When the player first reaches the city and approaches the Gym, the rival is seen exiting the Gym. He informs the player that Jasmine is not in the Gym and is instead tending to a sick Pokémon in Glitter Lighthouse. Jasmine will not return until the Pokémon is well again, requiring the player to bring her a SecretPotion to heal the sick Pokémon.
Unlike other Gyms, there are no Trainer battles before the Leader in this Gym. In Pokémon HeartGold and SoulSilver, two Trainers, Gentleman Preston and Lass Connie, are in the Gym, but they defer to battle, as they have already faced the player in the Lighthouse.
In HeartGold and SoulSilver, Jasmine will offer to trade the player a Steelix after they've earned all 16 Badges.
Olivine City has been famed for its water travel, thus a port was built to satisfy Olivine's connection with the sea. Olivine Port (Japanese: アサギみなとAsagi Port) has a ferry to Vermilion City, the S.S. Aqua, only accessible after entering the Hall of Fame and getting the S.S. Ticket from Professor Elm. The player can only ride it from Olivine City to Vermilion City on Mondays and Fridays due to the staff resting up.
After the initial trip to Kanto (which can happen on any day of the week), the S.S. Aqua sails from Kanto to Johto every Sunday and Wednesday, and sails from Johto to Kanto each Monday and Friday. Trainers can be encountered on the ship each voyage, and may be battled, but only once.
In HeartGold and SoulSilver, the captain of the ship implies that the S.S. Aqua travels to Sinnoh, as he mentions finding plates there. However, the ship does not appear in any of the games that take place in Sinnoh.
Olivine Café (Japanese: アサギしょくどうAsagi Café), spelled Olivine Cafe in Generation II, is a restaurant west of the Pokémon Center. It is known to be a place for Sailors to stop after a long trip on the sea to rest and eat. Olivine Café prides itself on its generous-sized menu that is "chock-full of hearty fare for beefy Sailors". The Café consists of a bar with many stools around it and a square table surrounded by seats. Many people there are happily eating their food; one nearly chokes because he hadn't chewed before he swallowed. A sailor who eats there gives away HM04 (Strength) in Generation II; however, in HeartGold and SoulSilver, the sailor at the bar will suggest going to Mt. Mortar to find Hikers with an extra HM04 instead, saying "Have you ever noticed that in the mountains, sometimes there are round boulders right in your way...? You can move them with the hidden move Strength! Hikers at Mt. Mortar sometimes have extra, or so I've heard...".
Once the player has obtained the Seal Case in HeartGold and SoulSilver, a young girl in the north-easternmost house of Olivine will give the player three random Seals once per day when one talks to her. There is also a Trainer inside the Pokémon Center that shows off her Ball Capsule with Seals.
A man in house northeast of Poké Mart will trade Voltorb for Krabby.
Battle Tower ad
In Crystal, a signpost advertises the Battle Tower. It reads BATTLE TOWER AHEAD Opening Now! (Japanese: 「このさき バトルタワー オープンちゅう！」). In the Japanese version, the 「オープンちゅう！」 part is omitted before the Pokémon Mobile System GB is enabled because the Battle Tower is closed while it is disabled.
In Pokémon HeartGold and SoulSilver, Olivine City's population is 46, a large size for a port city. Since Olivine is a port city, many Sailors and Fisherman stay here or even dwell in the city. The northern district is mainly an urban area, which dwells families and other people. Meanwhile, the southern district is host to many seaside tourist attractions, like the Glitter Lighthouse and the Olivine Café.
Olivine City first appeared in Fight for the Light!, where Ash and his friends arrived there, with Ash going straight to the Gym. Team Rocket was also in the city and headed to the Gym as well, but they stumbled across the Battle Tower. Ash battled Janina, who claimed to be Jasmine, until the real Jasmine came in and interrupted the battle. Jasmine was tending her sick Ampharos, Sparkle, and was unwilling to accept Ash's challenge until it was cured. As such, Ash and his friends departed to Cianwood City with Janina to get medicine for it.
The layout of the city is very similar to Sunyshore City with exits to the north and west of the city, two houses in the northeastern corner, a Gym in the northwestern corner, and a lighthouse in the southeastern corner where the city's Gym Leader can first be found. Both cities are located on the shore's edge. TM57 (Charge Beam) is also available in both. This might also explain why Jasmine is found visiting Sunyshore City.
There are unused maps in the Generation II games for a house in Olivine City that was not used in the final game. Inside, a woman mentions a pharmacy in Ecruteak City, not Cianwood City. This suggests that either the pharmacy could have been originally planned for Ecruteak City, or that Cianwood City may have been added to the game at the last minute.