The number of mountain operators has multiplied dramatically in recent years -- faster than the number of skilled experienced guides coming up through the ranks, so it's advisable to stick to a company with an established track record.

Chagga Tours LTD -- Chagga Tours was founded by mountain guide Michael Nelson Ntiyu of Tanzania and investor-hiker Christina Helbig of Germany. Michael, a Chagga who grew up on the mountain, has successfully guided hundreds of groups up the mountain (he has also climbed Mt. Everest) and is very attuned to the needs of climbers. Christina Helbig climbed with him twice and was so impressed by his leadership skills that she decided to build a tour company with him. Tours are not just mountain treks but can include stops at the cultural achievements of the Chagga, like the irrigation canals, built hundreds of years ago, which seem to flow uphill, and the terraced cultivation of plants in the Chagga farmlands. www.chagga-tours.com.

Marangu Hotel -- The family-run Marangu Hotel offered the first commercial climbs from their farmhouse in the 1930s, and their most senior guides have been working with the hotel for more than 40 years. Their climbs are not the cheapest (though they are certainly competitive), but they provide highly professional service with experienced guides and porters who queue up to work here (Marangu Hotel is a partner with the Kilimanjaro Porters Assistance Project). You have to stay at the Marangu Hotel to utilize their climbs. www.maranguhotel.com.

Nature Discovery -- This highly ethical company has been climbing since 1992 and focuses on top-end personalized expeditions. Kili climbs are only via the Machame and Shira routes and include the Western Breach ascent, with all safety precautions. Their cooks are said to be the best on the mountain, and their equipment is tip-top, from the modern mountaineering tents with ground sheets and cold-weather sleeping mats to large mess tents furnished with aluminum tables and chairs (with backs and armrests) and sanitary portable flush toilets inside enclosed tents. All guides are fluent in English and receive ongoing training. Their camping and lodge safaris are also highly rated. www.naturediscovery.com.

Hoopoe Adventure Tours -- The eco-friendly Hoopoe Safaris (now merged with Tropical Trails) is known for its semi-luxury safaris under canvas in Tanzania's National Parks. It also offers high-quality Kili climbs, with thick foam mattresses for all the igloo tents, a toilet tent, mess tent complete with tables and chairs, and high-frequency two-way radios for communication with base. Packages include overnight stays at The Arusha Hotel, the best hotel in Arusha center. www.hoopoe.com.

Jo Anderson Safaris -- Jo Anderson is a keen botanist who, after 50 climbs, is well versed on Kili flora and has three guides trained to do what he does so well: making the journey as special as the arrival at the summit. Safety is a top priority, and his team carries oxygen, a high-altitude pressure chamber, and a full wilderness medical kit on every climb. All support staff have first-aid qualifications and practical experience in wilderness first-aid. Flowers bloom at different times, but March through May is great for some (low season on the mountain), as is September and October. For more information on the best times to climb with Kili flora in bloom, contact him at jo@jo-anderson.com.

Zara Tours -- Owned by the dynamic Zainab, Zara Tours has been cornering the budget market for 2 decades and is, in this sense, by far the most successful outfit in Moshi, proudly claiming to put more people on the summit than anyone else. And Zara does offer a very competitive package, including airport transfers and 2 nights at their hotel (Springlands), with add-on tours elsewhere in Tanzania, though again, these are very much focused on the budget mass end of the market. You do not need to stay at Springlands to utilize Zara Tours, but it makes sense to, given that the accommodation is also geared toward saving money. www.zaratours.com.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.