Edinburgh's social infrastructure for solo travelers is built around the traditional Scottish pub — not the tartan-clad tourist premises of the Royal Mile, but the wood-paneled, whisky-focused locals of the New Town, the Grassmarket, and Leith. Cafe Royal Circle Bar on West Register Street (one of Britain's most beautiful Victorian bar interiors), Bennets Bar on Leven Street in Tollcross (unchanged since 1906), and Bow Bar on Victoria Street in the Old Town (the finest malt whisky selection in the city, no fruit machines, no music) are the three solo bars that Edinburgh regulars recommend without reservation. Sitting alone at the bar in these establishments is entirely normal, and the bartenders at Bow Bar in particular are excellent company.
The Old Town — the medieval ridge running from the castle to Holyrood — is atmospheric and architecturally extraordinary, but solo travelers who base themselves here should know that it quietens significantly after the tourist restaurants close. The Grassmarket area, with its independent pubs and proximity to the Cowgate's live music venues, is more animated in the evening. The New Town (the Georgian grid north of Princes Street) has a more relaxed, residential character: George Street's upscale bars, the independent café culture around Broughton Street and Stockbridge, and the excellent food scene of Thistle Street are all within easy walking distance.
Leith — Edinburgh's port neighborhood, a 30-minute walk or short bus ride from the center — has become the city's most interesting neighborhood for the independent-minded solo traveler. The Shore (the cobbled quayside) has an outstanding concentration of independent restaurants and bars, including The Kitchin (one Michelin star, Tom Kitchin), Restaurant Martin Wishart (one Michelin star), and half a dozen excellent seafood bistros that are completely off the tourist trail. The Leith Market (Saturday, 10am–3pm) on Dock Place is small but excellent for Saturday morning food grazing.
For practical solo navigation, Edinburgh is extremely walkable between the Old Town, New Town, and Marchmont, but the northern neighborhoods of Leith and Newhaven require a bus or the Ryde tram. The Lothian Buses day ticket (£4.20) gives unlimited travel on the city's excellent bus network. The Edinburgh Card (£34 for 24 hours) includes entry to most major attractions including Edinburgh Castle, Dynamic Earth, and Royal Yacht Britannia — excellent value if you're doing multiple paid attractions on a single day.