Inka have been running Aconcagua expeditions since 1991 and describe themselves as the mountain's specialists, with more than a thousand trips behind them. They are one of the established Mendoza outfitters, with an office in the city on Juan B. Justo where the pre-expedition briefing and kit check happen.
Beyond the Aconcagua ascents they run treks to its base camps and climbs on other Andean peaks. For anyone serious about the summit, the thing to look at is the ratio of guides to clients and the acclimatisation schedule — the good operators build in rest days that the cheap ones skip, and that difference is most of what decides whether people summit.
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