You can use this guide for Inazuma Eleven 3 Spark, Bomber and Ogre.
There are only few differences between their connection maps, this guide covers all of them.



Click on a panel:



Top-Left Panel



Players:
1: まるめ Marume - To the left of Raimon dorms.
2: ラクダ Rakuda - To the left of Toramaru's restaurant.
3: マッハ Mach - Football Association parking area.
4: あんこくじ Ankokuji - To the left of Raimon soccer field.
5: うきた Ukita - To the left of the warehouse in the shopping area.
6: ツーリング Touring - To the right of Toramaru's restaurant {you need a girl in the first four slots}.
7: べんてん Benten - To the left of Sally/Samantha's working place.
8: りんご Ringo (written in hiragana. In this connection map there's another girl with the same name, but in katakana) - Football Association parking area.

Locks:
*1: Clear the 3rd chapter.


Top-Center Panel



Players:
1: ごしょ Gosho - In the shopping area, on a manhole to the right.
2: かたたがえ Katatagae - Kyoto urban area, just before the stairs.
3: つばさ Tsubasa - To the right of Toramaru's restaurant.
4: あぶらだ Aburada - To the right of Toramaru's restaurant.
5: はなちゃん Hana-chan - Kyoto urban area, just before the stairs.
6: カウカ Cauca - To the left of Toramaru's restaurant.
7: いいのや Iinoya - Shopping area, right after the entrance.
8: クイーン Queen - To the right of the tech shop in the english area.
9: ぞうせん Zousen - Urban area in Hokkaido, in the middle of the 1st screen.
10: こしが Koshiga - In the shopping area, on a manhole to the right.
11: かいりき Kairiki - Sea Snake Island.
12: ぬしの Nushino - Near the mud field in Raimon.
13: みわ Miwa - In front of Fubuki's school, in the upper-left corner {you need a girl in the first four slots}.
14: いさ Isa - In the shopping area, on a manhole to the right.

Locks:
*1: Clear the 4th chapter.
*2: Clear the 3rd chapter.
*3: Clear the 6th chapter.


Top-Right Panel



Players:
1: メット Met - To the left of Toramaru's restaurant.
2: まいひめ Maihime - To the right of the tech shop in the english area.
3: よんきとう Yonkitou - To the left of Toramaru's restaurant.
4: なら Nara - Paw-shaped island, just before the stadium {you need at least 30 players in your team}.
5: ターコイズ Turquoise - To the right of the sports shop in Argentina area.
6: はぜくら Hazekura - Ehime docks, on the left {you need a girl in the first four slots}.
7: チョッパー Chopper - To the right of Toramaru's restaurant.
8: タイガー Tiger - Paw-shaped island.
9: ひらさわ Hirasawa - Peacock Island (the american one).
10: タートス Tortoise - Paw-shaped island.
11: ドラゴン Dragon - Paw-shaped island.

Locks:
*1: Recruit Demonio Strada of Team K.
*2: Clear the 7th chapter.

Chests:
A: Chikai no pendant (ちかいのペンダント) - Accessory: Body +6 and PT +10.


Left-Center Panel



Players:
1: かざま Kazama - To the right of the tech shop in the english area.
2: ういん Uin - To the right of the tech shop in the english area.
3: ひとだすけ Hitodasuke - To the left of Sally/Samantha's working place.
4: なかたに Nakatani - At the tech shop in Nara.
5: かぎなわ Kaginawa - In front of Inazuma Japan dorms, on the right.
6: セブン Seven - In front of the Titanic Stadium.
7: にしかわ Nishikawa - Peacock Island (american island).
8: らいめい Raimei - Sea Snake Island.

Locks:
*1: Recruit Dolphin of Big Waves.
*2: Clear the 5th chapter.
*3: Clear the 4th chapter.
*4: Clear the 6th chapter.

Chests:
A: Gakushou (がくしゅう) - The "Study" skill.


Middle Panel



Players:
1: ふたせ Futase - At the sports shop of the american area.
2: れいぜん Reizen - To the right of the tech shop in the english area.
3: なたに Natani - Parking area of Liocott Islands Hospital {you need a girl in the first four slots}.
4: かわわ Kawawa - To the left of Toramaru's restaurant.
5: ロデオ Rodeo - Behind the large sign in the american area.
6: おぺら Opera - At the techs shop in the italian area.
7: けいせい Keisei - Paw-shaped island.
8: あなざわ Anazawa - To the right of the tech shop in the english area.
9: やぶき Yabuki - To the left of Fauxshore/Yokato soccer field.
10: ライブラ Libra - 4th floor of the Condor Tower.
11: ケイト Kate - 1st floor of the Condor Tower.
12: アクア Aqua - 6th floor of the Condor Tower.

Locks:
*1: Clear the 7th chapter.


Right-Center Panel



Players:
1: さんぞう Sanzou - In front of the Condor Tower entrance.
2: ナイト Knight - Sea Turtle Island, right before the exit of the maze.
3: ゆうしゃ Yuusha - Sea Turtle Island, right before the exit of the maze.
4 SPARK/BOMBER: カレン Karen - Bottom-right corner of Mary Times/Oumihara soccer field, on the shore {you need a team level at least of 40}.
4 OGRE: タイセイ Taisei - 1st floor of the Condor Tower {you need a team level at least of 40}.
5: はなやま Hanayama - At the techs shop of the italian area.
6: ヴァーゴ Virgo - 1st floor of the Condor Tower {you need a girl in the first four slots}.
7: トップ Top - To the right of the sports shop of the italian area.
8: ゆめか Yumeka - Ehime docks, on the bottom-right corner.
9: しき Shiki - Sea Turtle Island, beginning of the maze.
10: ひめみや Himemiya - Ehime urban area, near the river (on the right).
11: ラー Ra - Paw-shaped island, in front of the argentinian stadium {you need at least 77 players in your team}.
12 OGRE: やみね Yamine - Cotarl area, in the middle of the first screen.

Locks:
*1: Clear the 9th chapter.
*2: Clear the 9th chapter.

Chests:
A: Ryuusei Blade (りゅうせいブレード Meteor Blade) - Hiroto's first shot, fire element, 49 TP, Block.
B: Kosmo mi├žanga (コスモミサンガ) - Accessory: Guts +12 (you can buy it in Raimon shop).
C: Boost Glider (ブーストグライダー) - Offense tech, fire element, 57 TP. You can buy it in Raimon shop.


Bottom-Left Panel



Players:
1: リンゴ Ringo (written in katakana. In this connection map there's another girl with the same name, but in hiragana) - To the right of the argentinian techs shop {you need a girl in the first four slots}.
2: ビーター Peter - At the argentinian sports shop {you need at least 32 players in your team}.
3: ともか Tomoka - Mary Times/Oumihara soccer field, top-right corner {you need at least 50 players in your team}.
4: ルル Lulu - To the right of the argentinian sports shop.
5: ガンガール Gungirl - In front of the american sports shop.
6: マルシャ Marcha - Near the recovery point of the brasilian area.
7: フエニクス Phoenix - Paw-shaped island {you need a girl in the first four slots}.
8: いしどこ Ishidoko - Fukuoka urban area, bottom right corner.
9: ファン Fan - To the right of the recovery point of the brasilian area.

Locks:
*1: Clear the 6th chapter.
*2: Clear the 8th chapter.


Bottom-Center Panel



Players:
1: ピエローヌ Pierrone - Up the soccer field in the italian area.
2: ジェンダー Gender - Behind the large sign in the american area.
3: そうりょ Souryo - Sea Turtle harbor.
4: ゴールド Gold - Ehime docks, on the left.
5: ミラノ Milan - To the right of the sports shop of the italian area.
6: メイジ Mage - Sea Turtle Island, beginning of the maze.
7: キャンサー Cancer - 6th floor of the Condor Tower.
8: ジェミニ Gemini - 1st floor of the Condor Tower.
9: カプリコン Capricorn - 4th floor of the Condor Tower.

Locks:
*1: Clear the 7th chapter.

Chests:
A: Hakai no glove (はかいのグローブ) - Gloves: Guard +8 (you can buy them at the italian and brasilian sports shop).


Bottom-Right Panel



Players:
1: リオ Rio - To the right of brasilian training point.
2: ビアンカ Bianca - To the right of italian sports shop.
3: ケムシ KMC - To the left of Fauxshore/Yokato soccer field.
4: しょうかん Shougan - Sea Turtle Island, at the beginning of the maze {you need a girl in the first four slots}.
5: トライアル Trial - To the right of brasilian training point.
6: ジャック Jack - Sea Turtle Island, right before the end of the maze.
7: ぶとうか Butouka - Sea Turtle Island, right before the end of the maze.
8: シーフ Thief - Sea Turtle Island, at the beginning of the maze.
9 SPARK/BOMBER: カオル Kaoru - To the right of the tech shop in the english area.
9 OGRE: レックウ Rekkuu - Near the mud field in Raimon.
10 OGRE: らいごう Raigou - Cotarl area, in the middle of the first scrren.

Locks:
*1: Clear the 10th chapter.
*2: Clear the 8th chapter.

Chests:
A: Kizuna no pendant (きずなのペンダント) - Accessory: Body +12.