Short answer — the top mobile network providers in Iran are:

• MCI (Hamrah-e Aval) — best overall nationwide coverage, strongest rural footprint and the largest subscriber base. (medialandscapes.org)
• MTN Irancell — strongest for mobile data (4G/4.5G/5G rollouts and high urban data speeds), very competitive plans. (en.wikipedia.org)
• RighTel — the third national operator; good in parts of major cities (was first with 3G), but much smaller market share and more limited coverage outside big cities. (en.wikipedia.org)

Other options:

• MVNOs and regional/specialist providers (e.g., Taliya, Shatel Mobile) operate on the major networks and can be cheaper or tourist-friendly (prepaid packages). They’re useful where you want low-cost prepaid SIMs or specific packages. (en.wikipedia.org)

Quick guidance on choosing:

• If you need reliable nationwide voice/SMS and rural coverage → choose MCI (Hamrah-e Aval). (medialandscapes.org)
• If you prioritize high mobile-data speeds in cities (streaming, large downloads) → choose MTN Irancell. (en.wikipedia.org)
• If you’re in a major city and want alternative plans or digital-first services → consider RighTel or an MVNO. (en.wikipedia.org)

If you want, I can:

• Compare current prepaid/data plans and prices for tourists vs residents (I’ll look up the latest packages), or
• Tell you how to buy/activate a SIM as a visitor in Iran and roaming options.

Which follow-up would you prefer?