---
title: "What are Ocean Alliances?"
description: "Explains ocean alliances: groups of carriers pooling vessel fleets to extend service and geographic coverage, why they exist, and how they cause blank sailings."
language: en
canonical: https://www.flex.thisisbrew.com/help/ocean-carrier-alliances/
lifecycle: live
---

# What are Ocean Alliances?

Ocean alliances are groups of carriers who have agreed to pool their fleet of vessels to extend their service offerings and geographic coverage.  

Three ocean alliances exist as of May 2018:

Alliances are pragmatic arrangements, so their compositions change every few years.  

For more details about each alliance, see ["Guide to Ocean Alliances"](https://www.flexport.com/blog/what-are-ocean-alliances/) on Flexport's blog. 

## Why do ocean alliances exist?

Alliances allow carriers to offer more sailing options with fewer vessels. If every carrier bought and operated the number of vessels needed to offer weekly sailings across every port they serve, the supply of vessel capacity would exceed the demand and container rates would fall. Carriers in an ocean alliance share their vessels so they can extend their service offerings and geographic coverage without flooding the market with vessels. 

## How do ocean alliances affect my shipments?

The merging of new ocean alliances will likely cause [blank sailings](https://www.flexport.com/glossary/blank-sailing/).

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*This is a markdown version of [https://www.flex.thisisbrew.com/help/ocean-carrier-alliances/](https://www.flex.thisisbrew.com/help/ocean-carrier-alliances/) for AI/LLM consumption.*