Getting there - land
Most overland border posts open from about 06.00 or 08.00, to 16.00 or 18.00, although a few of the busier ones, on main routes connecting with South Africa, stay open a few hours later than this.
Botswana has several border posts with Zimbabwe, of which the two most important are the one on the road between Kasane and Victoria Falls, at Kazungula (open 06.00–18.00) and the one on the main road from Francistown to Plumtree (and hence Bulawayo), at Ramokgwebane (open 06.00–18.00).
The third is a much smaller post at Pandametenga (open 08.00–16.00). This is 100km south of Kasane, and sometimes used by visitors as a neat short-cut into the back of Zimbabwe's Hwange National Park.
Despite their territories meeting only at a point, Botswana does have one border crossing to Zambia: a reliable ferry across the Zambezi linking Kazungula with its namesake village in Zambia. This ferry costs about US$25/£17 per vehicle, and runs from 06.00 to 18.00, weather permitting.
Despite the long length of its border with Namibia, Botswana has very few border posts.
The most important of these by far is the post on the Trans-Kalahari Highway, the route between the towns of Ghanzi and Gobabis. The Botswana side of this, Mamuno, is open 08.00 to 16.00, and so is the Namibian post at Buitepos on the other side.
There are two other main crossings. One is at Mohembo (north of Shakawe and at the south end of Namibia's Mahango National Park), that opens from 06.00 to 18.00. The other is across the Chobe River at Ngoma, which opens from 06.00 to 18.00.
There are two other possible crossings that you should know about. One is the option to cross the Kwando River by boat (only as part of an organised safari with these lodges), between the Botswana's Kwando concession, and Lianshulu Lodge in Namibia's Caprivi Strip. This obviously links two private areas, but the customs and immigration formalities are now in place to allow such a crossing.
The other is the road between Tsumkwe, in Namibia, and Nokaneng, on the west of the Delta, which is opening as an official border post. In doing so it will gradually, and probably radically, alter the options for routes in that whole area. Let's hope it has a positive effect on the Bushman communities in that region, and not the negative one that is widely feared.
To/from South Africa
South Africa has always been Botswana's most important neighbour politically and economically, and for many years (even before South Africa was welcome in the international fold!) it was in a 'customs union' with South Africa and Namibia. Thus it's no surprise to find a range of border posts with South Africa. In order from northeast to southwest these are:
• Pontdrift (open 08.00–16.00)
• Platjan (open 08.00–16.00)
• Zanzibar (open 08.00–16.00)
• Martin's Drift (open 08.00–18.00) to Groblersbrug
• Parr's Halt (open 08.00–16.00) to Stockpoort
• Sikwane (open 07.00–19.00) to Derdepoort
• Tlokweng, near Gaborone (open 08.00–16.00) to Kopfontein
• Ramotswa (open 07.00–19.00) to Swartkopfonteinhek
• Pioneer Gate, near Lobatse (open 07.00–19.00) to Skilpadshek
• Ramatlabama (open 07.00–20.00) to Ramatlabama
• Phitshane Molopo (open 07.30–16.30) to Makgobistad
• Bray (open 08.00–16.00)
• Makopong (open 08.00–16.00)
• Tshabong (open 08.00–16.00) to McCarthy's Rest
• Middlepits (open 08.00–16.00)
• Bokspits (open 08.00–16.00)