LONDON — Sixteen soccer teams from places largely excluded from international sport and diplomacy — among them Tibet, Tamil Eelam, Cascadia and Matabeleland — are seizing the chance to play in an alternative World Cup here in the British capital.

Coming from regions not recognized as sovereign nations by most of the world, the teams are banned from participating in the FIFA World Cup, which starts next week in Russia.

“By taking part, we can achieve visibility internationally for our people and our cause,” said Ferhat Mehenni, the president of the provisional government of Kabylia, a region in the Atlas Mountains of Algeria.

His team of Kabyls and their families were subject to threats and intimidation from the Algerian authorities ahead of the tournament, Mr. Mehenni said, speaking by phone from France, where he lives and works in exile.