Much has been done to open up the country by means of roads, including a trunk road from Mombasa, by Kibwezi in the upper Sabaki basin, and Lake Naivasha, to Berkeley Bay on Victoria Nyanza. But the most important engineering work undertaken in the protectorate was the construction of a railway from Mombasa to Victoria Nyanza, for which a preliminary survey was executed in 1892, and on which work was begun in 1896. The line chosen roughly coincides with that of the road, until the equator is reached, after which it strikes by a more direct route across the Mau plateau to the lake, which it reaches at Port Florence on Kavirondo Gulf. The railway is 584 m. long and is of metre (3.28 ft.) gauge, the Sudan, and South and Central African lines being of 3 ft. 6 in. gauge. The Uganda railway is essentially a mountain line, with gradients of one in fifty and one in sixty. From Mombasa it crosses to the mainland by a bridge half a mile long, and ascends the plateau till it reaches the edge of the rift-valley, 346 m. from its starting point, at the Kikuyu Escarpment, where it is 7600 ft. above the sea.

It then descends across ravines bridged by viaducts to the valley floor, dropping to a level of 6011 ft., and next ascending the opposite (Mau) escarpment to the summit, 8321 ft. above sea-level - the highest point on the line. In the remaining 100 m. of its course the level sinks to 3738 ft., the altitude of the station at Port Florence. The railway was built by the British government at a cost of £5,331,000, or about £9500 per mile. The first locomotive reached Victoria Nyanza on the 26th of December 1901; and the permanent way was practically completed by March 1903, when Sir George Whitehouse, the engineer who had been in charge of the construction from the beginning, resigned his post. The railway, by doing away with the carriage of goods by men, gave the final death-blow to the slave trade in that part of East Africa. It also facilitated the continued occupation and development of Uganda, which was, previous to its construction, an almost impossible task, owing to the prohibitive cost of the carriage of goods from the coast - £60 per ton.

The two avowed objects of the railway - the destruction of the slave trade and the securing of the British position in Uganda - have been attained; moreover, the railway by opening up land suitable for European settlement has also done much towards making a prosperous colony of the protectorate, which was regarded before the advent of the line as little better than a desert (see below, History). The railway also shows a fair return on the capital expenditure, the surplus after defraying all working expenses being £56,000 in 1905-1906 and £76,000 in 1906-1907.

Mombasa is visited by the boats of several steamship companies, the German East Africa line maintaining a fortnightly service from Hamburg. There is also a regular service to and from India. A cable connecting Mombasa with Zanzibar puts the protectorate in direct telegraphic communication with the rest of the world. There is also an inland system of telegraphs connecting the chief towns with one another and with Uganda.