| Name | Seto Inland Sea |
| Province ID | 1390 |
| Super region | West Pacific |
| Region | East China Sea |
| Area | Philipine Sea |
| Development | 6 |
| Base Tax | 3 |
| Base Production | 2 |
| Base Manpower | 1 |
| Trade node | Pest |
Here are the IDs of provinces that in on the same region as Seto Inland Sea:
| Province | Province ID |
|---|---|
| Amakusa Sea | 1389 |
| Bay of Komenskoie | 1382 |
| Bohai Sea | 4233 |
| Cenderawasih Bay | 1404 |
| Coast of Kamchatka | 1383 |
| Coast of Luzon | 1396 |
| Coast of Sakhalin | 1385 |
| Cuyo Archipelago | 4357 |
| Eastern Yellow Sea | 1374 |
| Hokkaido Coast | 4225 |
| Hokuriku Coast | 1980 |
| Izu Islands | 1439 |
| Japan Basin | 4226 |
| Kii Channel | 1391 |
| Korea Bay | 1375 |
| Kuril Islands | 1441 |
| Mariana Islands | 1435 |
| Mindanao Coast | 1402 |
| North Korean Sea | 1377 |
| Northern Philippine Sea | 1437 |
| Okhotsk Sea | 1384 |
| Olga Bay | 1378 |
| Palau Islands | 1403 |
| Philippine Sea | 1436 |
| Philippine Trench | 4358 |
| Ryukyu Islands | 1392 |
| Sanriku Coast | 1440 |
| Seto Inland Sea | 1390 |
| Shantar Islands | 1380 |
| South Korean Sea | 1376 |
| Soya Strait | 1386 |
| Taiwan Strait | 1372 |
| Tatar Straits | 1379 |
| Tauisk Bay | 1381 |
| Tokai Sea | 4224 |
| Tsugaru Strait | 1387 |
| Visayan Sea | 1397 |
| Volcano Islands | 1438 |
| Western Yellow Sea | 4234 |
| Yamato Basin | 1388 |
| Yang Tse Delta | 1373 |
Here are IDs of provinces that are in the same area as Seto Inland Sea:
| Province | Province ID |
|---|---|
| Cenderawasih Bay | 1404 |
| Coast of Luzon | 1396 |
| Cuyo Archipelago | 4357 |
| Izu Islands | 1439 |
| Kii Channel | 1391 |
| Mariana Islands | 1435 |
| Mindanao Coast | 1402 |
| Northern Philippine Sea | 1437 |
| Palau Islands | 1403 |
| Philippine Sea | 1436 |
| Philippine Trench | 4358 |
| Sanriku Coast | 1440 |
| Seto Inland Sea | 1390 |
| Tokai Sea | 4224 |
| Visayan Sea | 1397 |
| Volcano Islands | 1438 |