Coastal tower defense · iPhone & iPad
Coastal Defense - Sea Monster
Sea monsters are rising. Hold the coast!
Your heroes stand on the sea wall while crabs, eels, jellyfish and giant kaiju surge out of the waves. Pick your team, time your ultimates, play the tide — and don't let the wall fall.
- 10famous coasts
- 150levels
- 23heroes
- 10sea monster bosses
- 5elements
Ten coasts, ten sea monsters
Sail from Hawaii to the bottom of the Mariana Trench. Every coast has its own sea, its own wall and its own boss.
Chapter 1Volcano Bay
Hawaii
Chapter 2Shipwreck Strait
Bermuda Triangle
Chapter 3Coral Bay
Rio de Janeiro
Chapter 4Pyramid Shore
Egypt
Chapter 5Aurora Fjord
Norwegian Fjords
Chapter 6Burning Gulf
Dubai
Chapter 7Starlit Atoll
Maldives
Chapter 8Dragon Stone Bay
Ha Long Bay
Chapter 9Ancient Wall Shore
Great Wall
Chapter 10Mariana Abyss
Mariana Trench
Every boss plays differently
Each chapter ends in a kaiju with tricks of its own. Read the fight and bring the heroes that answer it.
Volcano Turtle
FireHawaii
Flies into a rage at 70 % and 30 % health, its shell cracking open over the lava inside.
Kraken
WaterBermuda Triangle
Grabs heroes off the wall with its arms — shoot the arm to free them — and calls up the tide.
Coral Queen
NatureRio de Janeiro
Heals while its coral buds stand and binds heroes in vines; Nature heroes slip free.
Sea Sphinx
EarthEgypt
Turns heroes to stone with its stare and raises obelisks that block straight shots.
Thunder Shark
LightningNorwegian Fjords
Dives out of reach with only its fin showing, then lunges at the wall with a stunning shock bite.
Magma Lionfish
FireDubai
Plants burning spines in the shallows that shield every monster in their lane.
Starlight Manta
WaterMaldives
Takes to the air, where only high, arcing shots can reach it, and turns the tide backwards.
Karst Hydra
NatureHa Long Bay
Three heads that grow back 12 seconds after you cut them — unless they are burning.
Fortress Crab
EarthGreat Wall
Carries a watchtower and a cannon on its back; until the tower falls, its shell takes half damage.
Abyssal Leviathan
Every elementMariana Trench
The five-phase final battle: it takes on the power of every sea, one rune after another.
The element circle
Every hero and every monster belongs to one of five elements. Hit the element you beat for more damage, and collect the Soul of each element from its monsters to raise the heroes you want.
×1.3 damage against the element you beat, ×0.7 against the one that beats you
- Water beats Fire
- Fire beats Nature
- Nature beats Earth
- Earth beats Lightning
- Lightning beats Water
23 heroes to raise
Level them up, raise their stars and watch their look change at every tier from 1★ to 6★. At 6★ the ultimate turns into its supreme form.
The Legendary heroes
Eight heroes of legend, each in a carved frame of their grade and element, shown here at 6★ with their supreme ultimate.
LegendaryTidesingerWaterUltimate: Song of the Deep
LegendaryMangrove DruidNatureUltimate: Ancient Mangrove
LegendaryThunder DrummerLightningUltimate: Drums of the Storm God
LegendaryDune SorceressEarthUltimate: Sea of Sand
MythicVolcano PriestessFireUltimate: Doomsday
MythicPirate QueenFireUltimate: Armada of the Dead
MythicAnchor GiantWaterUltimate: Abyssal Anchor
SupremeJade Dragon BladeNatureUltimate: Dragon Emperor
And fifteen more on the wall
One for every job: harpoons and cannons, vines and boulders, chain lightning and burning lanterns.
- HarpoonerWater
- CannoneerFire
- ArcherNature
- StonemasonEarth
- StormcallerLightning
- Coral KnightWater
- MinerEarth
- Storm HunterLightning
- Carnival Fire DancerFire
- Lotus PriestessNature
- Viking RunesmithEarth
- Pearl DiverWater
- Thunder SurferLightning
- Lantern GirlFire
- Bamboo Staff MasterNature
How you hold the coast
Defend the sea wall
Monsters rise from the sea across three lanes. Your heroes fire from the wall; every star you earn depends on how much of the wall is still standing.
Master the elements
From 4★ a hero awakens a second element and sets off one of 10 elemental reactions, such as Steam, Magma or Overload.
Raise your heroes
Level them up, raise their stars and unlock new ones with Soul and Mine. Each chapter brings a new hero who joins you as you reach it.
Play the tide
The tide rises and falls mid-battle: high water brings monsters in closer and faster, low water leaves them wading slowly over the sandbars.
Gear up and build
Equip each hero with a weapon, armour and a charm in four rarities, raise the sea wall through ten levels, and use bombs, barricades, repair kits and freezes in battle.
Come back every day
Daily and weekly missions, achievements, a daily shop with chests whose odds are shown up front, and Mine that keeps piling up while you are away.
Screenshots
At a glance
- Platforms
- iPhone and iPad, iOS 15 or later (portrait)
- Languages
- 15 languages, including English and Tiếng Việt
- Content
- 10 chapters, 150 levels, a boss for every chapter
- Connection
- Plays fully offline, no account needed
- Price
- Free, with optional in-app purchases
- Reminders
- Optional, scheduled on your device
- Progress
- Saved on your device
- Developer
- ISEMI
Questions
When can I play?
Coastal Defense - Sea Monster is coming soon to the App Store for iPhone and iPad. This page will link to the store listing as soon as it is live.
Is it free?
Yes. The game is free to download and play. Optional in-app purchases (Pearl packs, the Starter Pack and VIP) go through the App Store.
Do I need an internet connection?
No. The whole game runs on your device and plays offline. There is no account and no sign-in.
Where is my progress saved?
On your device only — there are no accounts or servers. Your progress is included in your normal iPhone or iPad backup, so restoring a backup restores your game. Deleting the app deletes its progress.
Can I change the language?
Yes. Open Settings from the home screen and pick any of the 15 languages, at any time.