Cast High Tide by paying {U}.
Activate two Islands by tapping them, adding {U}{U}{U}{U}.
Activate Oboro Breezecaller by paying {2} and returning a tapped Island to your hand, untapping another Island.
Activate Walking Atlas by tapping it, putting an Island from your hand onto the battlefield.
Whenever the Island enters the battlefield, Tideforce Elemental triggers.
Holding priority, activate Tideforce Elemental by paying {U} and tapping it, untap Walking Atlas.
Resolve the Tideforce Elemental trigger, untapping itself.
Repeat from step 2.

Infinite blue mana

Infinite landfall triggers

Tideforce Elemental

Oboro Breezecaller

Walking Atlas

High Tide

Activate a land by tapping it, adding at least {U}.
Activate Tideforce Elemental by paying {U} and tapping it, untapping Walking Atlas.
Activate Trench Behemoth by returning the land from the battlefield to your hand, untapping it.
Activate Walking Atlas by tapping it, putting the land from your hand to the battlefield.
When the land enters the battlefield, Tideforce Elemental triggers, untapping it.
Repeat.

Combos with "Tideforce Elemental"