eSIM MCP Servers Compared: What Your Agent Actually Gets (2026)

Two weeks ago this comparison covered five servers. It now covers thirteen, because between the start of September and today the field roughly tripled. If you ask Claude or ChatGPT to buy you mobile data, it will route you to whichever eSIM server it happens to know about — and the honest answer to “which one is best” depends on something most of these sites do not tell you: whether there is a server behind the badge at all.

We checked every provider on 21 September 2026 the only way that means anything: by opening the endpoint. Where a figure below is about someone else’s product it carries a link to their own page and the date we read it, and it is re-checked on a schedule. A comparison that rots is worse than none.

Six that rank for “eSIM MCP” and have no MCP server

This is the part worth reading first. Searching for an agent-ready eSIM returns a set of sites that market themselves to AI agents. For six of them we could not find a server of any kind — no endpoint that answers, no package, no repository, no entry in the official MCP registry or in Glama, PulseMCP or mcp.so:

• esim.dog — documents a REST API behind a Bearer key. The MCP claim has no endpoint behind it.
• ZeroID, anonesim.io, cryptoesim.io, cypheresim.com, encryptsim.com — crypto/no-KYC eSIM shops. Good at what they are; none of them exposes an agent interface.

None of that makes them bad products. It does mean that if your agent is told to “use one of the eSIM MCP servers” and picks one of these, it will fail, and the failure will look like your agent’s fault. We were wrong about one of these ourselves: in the 7 September version of this page we listed esim.dog as “claimed, not yet documented”, implying a server was on the way. On re-checking we found positive evidence there is none.

The four questions that separate the rest

Marketing aside, eSIM MCP servers differ on four axes, and they decide whether your agent completes a purchase in one conversation or stalls on a signup form:

1. What does browsing cost? Can the agent see the catalog anonymously, or does the very first tool call need a key?

2. What does buying cost? An API key from a dashboard, an OAuth dance, a partner contract — or nothing but a funded balance?

3. What shape is the pricing? Fixed packages with validity windows force the agent to predict usage; metered billing lets it pay for what the task consumed.

4. Which rails, and whose name? Cards need a cardholder. Stablecoins don’t. KYC requirements decide whether an autonomous agent can be the customer at all.

All thirteen live servers, at a glance

Tool counts read from each server’s own tools/list or its entry in the official MCP registry on 21 September 2026. “Local install” means stdio — the agent cannot reach it over the network; someone has to install a package on the machine first.

The column that matters most is the last one. Twelve of the thirteen sell fixed packages: a data bundle with a validity window, which the agent has to size before it knows what the task will use. Only Roamzy meters. eSIMfly is the one partial exception — it has a business “Pay As You Go” product billed per megabyte, but does not publish its rates, so an agent cannot price it.

What a gigabyte in Japan actually costs

Tool counts are easy to compare and tell you nothing. Here is the same purchase across the field — one gigabyte in Japan — as each vendor sells it:

Two things are going on in that table. The obvious one is the sticker price. The one that costs more money is the last column: a package is charged in full whether the agent uses all of it or a tenth of it, and the remainder dies on the expiry date. If your agent buys a 1 GB package and the task consumes 120 MB, the effective rate is roughly eight times the sticker. Metered billing has no such gap, which is also why our number is a rate rather than a price — you are looking at what a full gigabyte would cost, not at what you must spend.

Across the catalog the floor is $0.61 per GB and the median is $3.69 per GB, over 193 countries on one eSIM. Some countries are dearer than a package; most are not, and none of them expires.

Roamzy — anonymous-first, metered, no expiry

Our server is built around one bet: the agent should never leave the conversation. https://roamzy.io/mcp answers without authentication — an anonymous account is created on the first tool call, and buying needs nothing beyond a funded balance. No API key, no OAuth screen, no email. Twelve tools cover the catalog, estimates, ordering, top-ups, usage and referrals: see eSIM for AI agents for the full flow and the MCP server page for setup.

Honest limits. Rails are USDT and USDC only — no cards, by design, because a card needs a cardholder. The minimum top-up is $20, which is more than any single package in the table above; that is the floor the payment rail imposes, and it is the real reason to buy from someone else if all you want is one gigabyte once. The balance never expires, so the money is not spent, but it does have to be committed up front. An anonymous agent account is also capped tighter than a claimed one — $40 a day, $100 a month, one active eSIM — and a single order over $50 is refused rather than escalated, because an anonymous account has no human to ask.

eSIM Tabby — the closest thing to a direct competitor

Tabby is the only other server here built for agent payment rails: card via Stripe, or USDC over x402 on Base. That is genuinely the same bet we are making, and worth testing against ours.

The difference is where the gate sits. Tabby’s endpoint completes an MCP handshake anonymously, and then the first real call stops: tools/call on its search tool returns 401 with an OAuth challenge. An agent must sign a human in before it can so much as look at a price. Their own agent page says it plainly — the first tool call runs an OAuth flow, the user signs in, and the agent gets a token scoped to that account. For a delegated assistant working on behalf of someone already sitting there, that is fine. For an autonomous agent, it is the end of the road. Prices are readable without signing in, but only through their website, not through the protocol.

PikaSim, and the rest of the field

PikaSim ships the largest implementation — 31 tools, up from 15 two weeks ago — with the widest rails of anyone: Bitcoin, Lightning, Monero and USDT, and a $10 wallet minimum that is half of ours. Browsing is anonymous; buying needs a wallet code. If your agent values Lightning or Monero over metered billing, this is the one to test against us.

nadanada and ALT eSIM are the other two that let an agent buy without an account — both remote, both packages, both worth a look if you want a small one-off purchase without a $20 commitment. BuyUKeSIM has the widest crypto list in the field, including Monero, but needs an API key. eSIMfly, eSIM Access and eSIM Copilot are business integrations: OAuth or partner credentials, aimed at companies reselling eSIMs rather than at an end user’s agent. VoidMob, CheapereSIM, Letisim and Worldcitisim publish stdio servers, which means someone installs a package locally first — a real option for a developer, not something a hosted assistant can reach.

Try it in one paste

Point any MCP client at the streamable-HTTP endpoint and ask it to price a trip — no account first:

{
  "mcpServers": {
    "roamzy": { "url": "https://roamzy.io/mcp" }
  }
}

The first tool call creates an anonymous account with tight default limits; funding it is a stablecoin invoice away. If you would rather see it work before paying anything, a verified account on the website gets its first eSIM issued with about 100 MB of credit already on it — that route is the dashboard, not the API, and the agent path still starts at the $20 minimum. Live rates are on /prices, the full agent flow on /ai-agents, and the background in Best eSIM for AI agents and how agents pay with x402 & stablecoins.

Verdict

Start by discarding the six that have no server. Of the thirteen that remain, only five let an agent buy anything without a human creating an account first, and only one bills for what the task actually used. If your agent needs one eSIM inside one conversation with no setup, that shape is ours. If you want a single small package and do not want to commit $20, nadanada or ALT eSIM will sell you one. If Lightning or Monero matter more than metering, PikaSim. If you are a business reselling eSIMs, eSIM Access or eSIMfly. And if a provider’s agent story is a badge on a landing page with no endpoint behind it, it is worth exactly what your agent can fetch from it.