The Dois Irmãos hike gives you one of Rio's best viewpoints: a steep but short climb up the twin peaks behind Vidigal favela that opens onto a sweeping panorama of Ipanema, Leblon, the lagoon, and both beaches curving into the distance. Expect 45-90 minutes up depending on fitness, a mix of dirt trail, stone steps, and a final scramble. It's moderately steep with some exposure near the top, but nothing technical. The view is genuinely spectacular on clear days; on hazy ones it's still decent but loses the crisp postcard effect. You'll share the summit with a steady stream of locals and tourists, especially at sunset.
Best time is the dry season from May to September when rain is less likely and visibility is better. Avoid the peak of summer (Dec-Feb) unless you love sweaty hikes in 35°C heat with afternoon thunderstorms. Expect to pay around $30-70 total per person including transport from central/south zone, a local guide, and water/snacks. Independent hikers can do it cheaper but shouldn't go alone for safety.
Tip: go with a small group and a local guide from Vidigal – it's safer and they know the current trail conditions. Skip trying to do it at sunrise unless you're staying in Vidigal; the logistics from most hotels aren't worth it. Bring plenty of water, wear proper shoes, and don't take valuables.