Coastal Access Colonization

EU5 applies the landlocked colonial migration penalty individually to each colonial charter. However, the only moddable colonial migration modifier available to us is country-wide.

The vanilla ×0.05 penalty is hardcoded into the game and cannot currently be removed or modified directly through normal EU5 scripting. This mod therefore compensates for it by temporarily granting:

+1900% Monthly Colonial Migration

This produces the intended result:

×0.05 ×20 = ×1.00

Because the compensation is global, it cannot safely remain active once one of your colonial charters has established a foothold. Vanilla stops applying the ×0.05 penalty to that charter as soon as you own a location inside its target area.

To prevent established colonies from receiving an unintended ×20 bonus, the mod now behaves as follows:

• The compensation activates when at least one colonial charter is active and all active charters are still unestablished.
• The compensation remains active if you have several charters, provided none of them owns a location in its target area.
• The compensation immediately deactivates when any active charter establishes its first owned location.
• It can activate again after the established charter is completed or otherwise removed, provided the remaining charters are still unestablished.

This is the cleanest fully automatic implementation currently possible through the normal Steam Workshop modding system.

In vanilla EU5, countries whose capital region has no coastline receive a severe ×0.05 colonial migration penalty, even if they control developed coastal cities and ports elsewhere.

This mod allows an inland country to overcome that penalty once it controls enough coastal population, development, and infrastructure to plausibly support overseas migration.

Owning a single insignificant coastal village is not enough. The country must meet one of the coastal capacity tiers listed below.

All of the following must be true:

• Your capital’s region contains no coastal location.
• You have at least one active colonial charter.
• Every active colonial charter is still unestablished.
• Your country satisfies at least one of the coastal access tiers below.

A charter is considered established once you own at least one location inside its target province area.

You only need to satisfy one of the following options:

• 1 coastal location
• At least 50,000 population
• At least 20 development
• Must be a City or Megalopolis

Each of the two locations must have:

• At least 25,000 population
• At least 12 development
• Must be a Town, City, or Megalopolis

Each of the three locations must have:

• At least 15,000 population
• At least 8 development
• Must be a Town, City, or Megalopolis

Each of the five locations must have:

• At least 8,000 population
• At least 5 development
• May be a Rural Settlement, Town, City, or Megalopolis

Every location counted toward a tier must satisfy all requirements of that tier.

For example, the two-port tier requires two coastal locations that each have at least 25,000 population, 12 development, and town rank or higher.

One developed city and one insignificant coastal village will not qualify.

The locations do not need to be adjacent. They represent the country’s combined coastal infrastructure and capacity to move people overseas.

One unestablished charter:
Compensation active

Three unestablished charters:
Compensation active

One charter establishes its first location:
Compensation inactive

One established charter and one new unestablished charter:
Compensation inactive

The established charter is completed or removed:
Compensation may activate again for the remaining unestablished charter

This restriction is necessary because the migration compensation affects the entire country rather than one individual charter.

• Uses a standalone automatic country modifier.
• Does not overwrite vanilla game files.
• Should be compatible with most other mods.
• May conflict with mods that heavily alter colonial migration or use the same modifier.
• The mod does not modify the EU5 executable.

Owning a random coastal village should not instantly give a large inland realm the same colonial capacity as an established maritime state.

A major port city can support overseas migration by itself, while several smaller ports can collectively provide the necessary population, administration, ships, and infrastructure.

The temporary nature of the compensation also means inland countries can establish an overseas foothold without granting permanently inflated migration to their existing colonies.