Before you start

A determination of whether you are tax-resident
RUC and SRI online credentials, if you have independent income
A municipal account with the Alcaldía de Machala, if you own property or trade here
Records of foreign income, of outbound transfers and of border crossings

Step-by-step

1
Establish whether you are tax-resident
The principal test is presence in Ecuador for more than 183 days, continuous or not, within a twelve-month period falling in the fiscal year. There is also a test based on the core of your economic activities or interests. Living an hour from Peru means the day count is genuinely worth tracking rather than estimating.
OnlineWho: You
2
Understand that residence means worldwide income
An Ecuadorian tax resident is taxable on Ecuadorian and foreign-source income alike, with relief for foreign tax paid in defined circumstances. Foreign pensions, foreign rental income, foreign dividends and foreign capital gains are all in scope. This is the opposite of the territorial position in Costa Rica and Panama.
OnlineWho: You
3
Let withholding handle a straightforward salary
Employers withhold income tax monthly against the annual progressive schedule and you submit your projected deductible personal expenses to them. Employees with a single employer and no other income generally have nothing further to file.
Via employerWho: Your employer
4
Get a RUC and check whether RIMPE applies to you
Independent professionals, landlords and businesses register for a RUC, issue electronic invoices through the SRI system and file periodically. Smaller taxpayers may fall within the simplified RIMPE regime, which has bands with different rates and different filing frequencies. In a province full of small growers and traders this is the practical question, and it is not obvious from the outside which band applies.
OnlineWho: You
5
Read the municipal tax gazette and register the patente
Machala publishes its gaceta tributaria municipal setting out its own charges, their bases and their calendar. The patente municipal is required of anyone carrying on economic activity in the canton and the impuesto predial is charged on property, both on a calendar entirely separate from the SRI's. Given how much the municipality runs here, this is a more consequential document than in most Ecuadorian cities.
OnlineWho: You
6
If your income touches the export trade, add customs to the picture
Anyone exporting bananas, shrimp or anything else deals with SENAE, the customs authority, on top of the SRI — export declarations, origin documentation and the drawback and refund regimes that go with them. This is an entirely separate authority with its own registration and its own system, and it is where most of the professional accounting work in this province actually is.
OnlineWho: You

Documents you’ll need

Cédula de identidad
RUC and SRI credentials, where applicable
Employer withholding certificate
Municipal patente and predial records, if you trade or own property
Records of days present in Ecuador, border crossings and outbound transfers

Things most newcomers don’t know

Ecuador taxes residents on worldwide income, which is the opposite of what most people assume about the region.

Costa Rica and Panama are territorial; Ecuador is not. Once tax-resident here, foreign pensions, foreign rental income, foreign dividends and foreign capital gains are in scope, with relief for foreign tax paid in defined cases. People comparing Latin American destinations frequently carry the territorial assumption across the whole region and get this exactly backwards. It is the most consequential single fact in this guide.

Source: SRI

Two different rules read the same passport stamps, and near a land border they diverge fast.

More than 183 days present makes you tax-resident; more than 90 days absent costs you your temporary residence. Both are computed from your entries and exits, and with Peru an hour away those stamps accumulate quickly and casually. Someone arranging their year around one rule can easily walk into the other. Keep a single spreadsheet of every crossing and check it against both before planning anything long.

Source: SRI; MREMH

The municipality's gazette matters more here than in most Ecuadorian cities.

Machala's GAD runs water, mobility, markets, waste, its fire service and a municipal health network through its own public companies, and levies the patente and predial on its own calendar through its own portal. None of it appears in the SRI's system or generates a national reminder. Because so much of ordinary life here runs through the municipality rather than the state, reading the gaceta tributaria once is a genuinely higher-value hour than it would be in Quito.

Source: Alcaldía de Machala

Your filing deadline depends on the ninth digit of your identification number.

Ecuador staggers national filing deadlines across a month according to the ninth digit of your RUC or cédula, so no two taxpayers necessarily share a date. Newcomers look up 'the deadline', find a range, and pick the wrong end of it. Look up your own digit once and diary it; late filing carries interest and fines that accrue from your date, not from the last one.

Source: SRI

Common mistakes to avoid

Assuming Ecuador is territorial like Costa Rica or Panama, when it taxes residents worldwide.
Estimating days present and days absent rather than logging every border crossing.
Registering a RUC with the SRI and never registering the patente municipal.
Assuming the general regime applies when a small business is actually within RIMPE.
Missing your own staggered filing deadline by using a general one.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.