The member cities
At its height the International Black Sea Club listed around twenty-seven member cities and municipalities, drawn from every shore of the Black Sea and reaching into the eastern Mediterranean. They ranged from great ports of more than a million people to smaller harbour towns, but all shared a maritime character and an interest in the sea that joined them. The cities below are listed as they appeared in the Club's own historical materials; several have detailed heritage profiles on this site.

Cities around the sea
Grouped by country, the membership and associated cities documented for the Club included:
- Ukraine and its ports: Odessa, Ilyichevsk, Yuzhniy, Nikolayev, Kherson, Mariupol, and the Crimean ports of Sebastopol, Yalta and Feodosiya.
- Russia: Rostov-on-Don, Taganrog, Azov, Anapa, Tuapse, Temryuk and Stavropol.
- Georgia: Batumi and Poti, with Sukhum on the Abkhaz coast.
- Turkey: Trabzon, Samsun and Izmit.
- Romania: Constanta and Galati.
- Bulgaria: Varna and Bourgas.
- Greece: Thessaloniki, Piraeus and Kavala.
- Italy: Trieste, at the head of the Adriatic.
- Moldova region: Tiraspol on the Dniester.
The list reflects the Club's own roll of members and participants at various times and is presented for historical reference only; it is not a statement about the present status of any city. Sources differ slightly on the exact membership at any given moment — the Club described itself as having around twenty-seven members while listing rather more cities as participants — and this reference does not attempt to fix a single definitive roll.
A cross-section of the sea
Taken together, the member cities formed a remarkable cross-section of the Black Sea world. There were million-strong metropolises and quiet harbour towns; ancient Greek foundations and cities barely two centuries old; resorts, naval bases, oil terminals and grain ports. What they shared was the sea and a dependence on it, and it was this common maritime life — rather than any shared language, faith or history — that the Club took as its foundation. The individual profiles below trace how a few of these cities came to sit around the same table.
Heritage profiles
Detailed heritage pages are available for a selection of the Club's best-known ports:
- Odessa — the cosmopolitan northern port where the Club was founded.
- Constanta — Romania's ancient sea gate on the western shore.
- Varna — Bulgaria's maritime capital and sea-garden city.
- Thessaloniki — the great Aegean port and Mediterranean partner.
- Trabzon — the historic Pontic harbour of the southern coast.
- Batumi — Georgia's Black Sea gateway on the eastern shore.
For the maritime setting these cities share, see heritage & culture; for the practical ties between them, see Black Sea cooperation.