För de brittiska guiderna verkar svaret vara att det inte finns några alternativ till Azkaban om du är fängslad.
Allt började när den internationella sekretesslagen infördes. Det verkade mindre mindre bevakade fängelser var lättare att flyga och drog Muggle Attention, som du förväntar dig att slang är att utföra magi.
Once the International Statute of Secrecy had been imposed, the Ministry of Magic felt that the small wizarding prisons that existed up and down the country in various towns and villages posed a security risk, because attempts by incarcerated witches and wizards to break out often led to undesirable bangs, smells and light shows. A purpose-built prison, located on some remote Hebridean island, was preferred, and plans had been drawn up when Damocles Rowle became Minister for Magic.
Azkaban gav en effektiv lösning till synes oavsett det brott som begåtts.
In spite of opposition from many wizards, among them experts on both Dementors and buildings with Azkaban’s kind of Dark history, Rowle carried out his plan and soon a steady trickle of prisoners had been placed there. None ever emerged. If they were not mad and dangerous before being placed in Azkaban, they swiftly became so.
ibid
När en gång började jobba på jobbet, så var det bara en minister av magi (tills Shacklebolt) någonsin tittat på ett alternativ, men det var för lite för sent. Det fanns också en rädsla för att demenserna skulle lämna ön och letade efter fler själar att föda på.
Rowle was succeeded by Perseus Parkinson, who was likewise pro-Azkaban. By the time that Eldritch Diggory took over as Minister for Magic, the prison had been operating for fifteen years. There had been no breakouts and no breaches of security. The new prison seemed to be working well. It was only when Diggory went to visit that he realised exactly what conditions inside were like. Prisoners were mostly insane and a graveyard had been established to accommodate those that died of despair.
Back in London, Diggory established a committee to explore alternatives to Azkaban, or at least to remove the Dementors as guards. Experts explained to him that the only reason the Dementors were (mostly) confined to the island was that they were being provided with a constant supply of souls on which to feed. If deprived of prisoners, they were likely to abandon the prison and head for the mainland.
This advice notwithstanding, Diggory had been so horrified by what he had seen inside Azkaban that he pressed the committee to find alternatives. Before they could reach any decision, however, Diggory caught dragon pox and died. From that time until the advent of Kingsley Shacklebolt, no Minister ever seriously considered closing Azkaban. They turned a blind eye to the inhumane conditions inside the fortress, permitted it to be magically enlarged and expanded and rarely visited, due to the awful effects of entering a building populated by thousands of Dementors. Most justified their attitude by pointing to the prison’s perfect record at keeping prisoners locked up.
ibid
För andra länder verkar det finnas andra fängelser ... eller åtminstone en som vi känner till.
Vi vet att Gellert Grindelwald var låst i Nurmengard-fängelset när Voldemort slog fast med honom.