Before you start

A determination of whether you are domiciled or non-domiciled
RUC and Clave SOL, if you have independent income
Payroll withholding certificates, if employed
Records of days present in and absent from Peru

Step-by-step

1
Model your take-home on the non-domiciled rate first
A flat 30% of gross with no deductions and no 7 UIT allowance applies until domicile is acquired. On a Cusco salary that is a substantial difference from the progressive scale, and it applies for your whole first stretch.
OnlineWho: YouBefore accepting an offer
2
Count the days, then count to the following January
More than 183 calendar days of presence within any twelve-month period makes you domiciled, but only from 1 January of the next tax year. Someone arriving after the middle of the year spends a long time on the flat rate. SUNAT works from immigration records, so your own log should match them.
OnlineWho: You
3
Get a RUC if you guide, host, let or freelance
Independent income of any kind means a RUC and periodic filing. Cusco's economy is full of exactly this activity, and doing it informally leaves you outside the tax system and outside any route to permanent residence.
OnlineWho: You
4
Issue electronic receipts through SUNAT's system
Peru's electronic invoicing regime is comprehensive. Independent professionals issue recibos por honorarios electronically; businesses issue facturas or boletas. Clients that are companies will insist on it.
OnlineWho: You
5
File the annual declaration in the SUNAT window
The annual declaration for the previous calendar year falls in the first months of the following one, on a calendar SUNAT publishes with deadlines staggered by the last digit of your RUC.
OnlineWho: YouMarch–April
6
Handle the municipal charges with your district
Impuesto predial and arbitrios are declared and paid to the district municipality — Cusco, Wanchaq, San Sebastián, San Jerónimo or Santiago — each with its own rates and its own counter. If you let a property, the district also matters for the licences a short-term rental may need.
In personWho: You

Documents you’ll need

Carné de extranjería
RUC and Clave SOL, where applicable
Annual withholding certificate from an employer
Record of days present in and absent from Peru
Municipal property declarations

Things most newcomers don’t know

The 1 January rule punishes mid-year arrivals, and Cusco's season pushes people to arrive mid-year.

Domicile is acquired by exceeding 183 days in a twelve-month period, but applies only from the following 1 January. Cusco's hiring cycle draws people in around April and May for the high season, which is precisely the timing that leaves you on the flat 30% for the remainder of that year and then only switches the January after next in some patterns. If you have any flexibility on your start date, it is worth modelling both.

Source: SUNAT

Most Cusco income is independent income, which means a RUC and real filing obligations.

Guiding, hosting, letting a room, teaching and freelancing are all independent activity under Peruvian tax law, requiring a RUC, electronic receipts and periodic returns. A great deal of it happens informally here. The problem is not only the tax exposure: informal income cannot evidence means of subsistence for a residence renewal, and it leaves you invisible to a system you will eventually need.

Source: SUNAT

Short-term letting is a municipal question as well as a tax one.

Letting a property to visitors puts you inside both SUNAT's rules on rental and business income and the district municipality's rules on licences and land use. Cusco's districts each administer these separately, and the historic centre has additional heritage constraints on what a building may be used for. Anyone buying a flat here to let should ask both authorities before assuming a listing is lawful.

Source: SUNAT; Municipalidad Provincial del Cusco

Once domiciled, Peru taxes you on worldwide income and nobody sends a notification.

Domicile brings foreign rental income, dividends and gains into the Peruvian net. The change happens automatically on 1 January, with no letter and no prompt. For the many people in Cusco who keep property or investments at home, the year before that switch is when advice is worth taking — not the April after it, when the options have narrowed.

Source: SUNAT