(ガラムサイズ水路, Garamusaizu Suiro)

"𝘏𝘦𝘺, 𝘭𝘰𝘤𝘬 𝘵𝘩𝘪𝘴 𝘱𝘭𝘢𝘤𝘦 𝘶𝘱 𝘧𝘰𝘳 𝘮𝘦, 𝘸𝘪𝘭𝘭 𝘺𝘰𝘶? 𝘐𝘧 𝘔𝘪𝘨𝘦𝘭𝘰 𝘧𝘪𝘯𝘥𝘴 𝘰𝘶𝘵 𝘸𝘦'𝘷𝘦 𝘣𝘦𝘦𝘯 𝘥𝘰𝘸𝘯 𝘩𝘦𝘳𝘦, 𝘩𝘦'𝘭𝘭 𝘵𝘢𝘯 𝘰𝘶𝘳 𝘩𝘪𝘥𝘦𝘴."

—Vaan to Kytes

The Garamsythe Waterway is a location in the land of Ivalice in Final Fantasy XII. It serves as the sewer system for Rabanastre. The Garamsythe Waterway spans the underneath of the city, and is accessed via Lowtown. After the Esper Zalera is defeated deep within the Barheim Passage, a zoning point to the waterway becomes available.

The waterway is a labyrinth of water and passages with monsters roaming the pathways. The water's level can be adjusted to reveal lower pathways through the opening and closing of the sluice gates.

Because the waterway is of water terrain, all Water and Lightning attacks deal 20% more damage than normal, and Earth damage is halved.

The waterway contains multiple treasures, but in the original version they are mainly common items and low level equipment, unless they have gil. With the Diamond Armlet equipped, the treasures contain Knots of Rust as a common item, and Elixir or Hi-Ether as a rare item.

When Vaan is on his way to the palace, he passes through the North Spur Sluiceway. In the original version, it is possible to obtain two weapons here. Oak Staff in a treasure right in the middle of the area that spawns 65% of the time, has 70% chance to contain items instead of gil, and when it contains items it can be either the Oak Staff or a Potion. The treasure respawns. Right before the stairs leading up toward the palace there is a treasure that spawns 65% of the time, and when it contains an item, it yields a Mage Masher.

In the Zodiac versions, the treasures are different. No. 4 Cloaca Spur (Drained) has the useful Achilles technick.