diff --git a/package.json b/package.json
index 3774d76..42efd1f 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,7 @@
     "@eslint/js": "^9.39.2",
     "@types/make-fetch-happen": "^10.0.4",
     "@types/node": "^25.0.2",
-    "@vitest/coverage-v8": "^4.0.15",
+    "@vitest/coverage-v8": "^4.0.17",
     "eslint": "^9.39.2",
     "eslint-config-prettier": "^10.1.8",
     "make-fetch-happen": "^15.0.3",
@@ -22,9 +22,11 @@
     "tsdown": "^0.19.0",
     "typescript": "^5.3.3",
     "typescript-eslint": "^8.49.0",
-    "vitest": "^4.0.15"
+    "vitest": "^4.0.17"
   },
   "workspaces": [
-    "packages/*"
+    "packages/tide-predictor",
+    "packages/neaps",
+    "packages/cli"
   ]
 }
diff --git a/packages/cli/bin/dev.cmd b/packages/cli/bin/dev.cmd
new file mode 100644
index 0000000..c72d7dc
--- /dev/null
+++ b/packages/cli/bin/dev.cmd
@@ -0,0 +1,3 @@
+@echo off
+
+node --no-warnings=ExperimentalWarning "%~dp0\dev" %*
diff --git a/packages/cli/bin/dev.js b/packages/cli/bin/dev.js
new file mode 100755
index 0000000..4b9d0ff
--- /dev/null
+++ b/packages/cli/bin/dev.js
@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+
+import { execute } from "@oclif/core";
+
+await execute({ development: true, dir: import.meta.url });
diff --git a/packages/cli/bin/run.cmd b/packages/cli/bin/run.cmd
new file mode 100644
index 0000000..968fc30
--- /dev/null
+++ b/packages/cli/bin/run.cmd
@@ -0,0 +1,3 @@
+@echo off
+
+node "%~dp0\run" %*
diff --git a/packages/cli/bin/run.js b/packages/cli/bin/run.js
new file mode 100755
index 0000000..94a0d6f
--- /dev/null
+++ b/packages/cli/bin/run.js
@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+
+import { execute } from "@oclif/core";
+
+await execute({ dir: import.meta.url });
diff --git a/packages/cli/package.json b/packages/cli/package.json
new file mode 100644
index 0000000..06754a9
--- /dev/null
+++ b/packages/cli/package.json
@@ -0,0 +1,55 @@
+{
+  "name": "@neaps/cli",
+  "version": "0.1.0",
+  "description": "Command line interface for Neaps tide prediction",
+  "keywords": [
+    "tides",
+    "harmonics"
+  ],
+  "homepage": "https://github.com/neaps/neaps#readme",
+  "bugs": {
+    "url": "https://github.com/neaps/neaps/issues"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/neaps/neaps.git",
+    "directory": "packages/cli"
+  },
+  "license": "MIT",
+  "author": "Brandon Keepers <brandon@openwaters.io>",
+  "type": "module",
+  "main": "dist/index.cjs",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js",
+      "require": "./dist/index.cjs"
+    }
+  },
+  "files": [
+    "dist"
+  ],
+  "bin": {
+    "neaps": "./bin/run.js"
+  },
+  "scripts": {
+    "build": "tsc -b",
+    "prepack": "npm run build",
+    "test": "vitest"
+  },
+  "dependencies": {
+    "@oclif/core": "^4.8.0",
+    "neaps": "^0.2"
+  },
+  "oclif": {
+    "bin": "neaps",
+    "commands": "./dist/commands",
+    "dirname": "neaps",
+    "topicSeparator": " "
+  },
+  "devDependencies": {
+    "@oclif/test": "^4.1.15",
+    "@types/node": "^18.19.130",
+    "nock": "^14.0.10"
+  }
+}
diff --git a/packages/cli/src/command.ts b/packages/cli/src/command.ts
new file mode 100644
index 0000000..f7b8d68
--- /dev/null
+++ b/packages/cli/src/command.ts
@@ -0,0 +1,13 @@
+import { Command, Flags } from "@oclif/core";
+import getFormat, { availableFormats, type Formats, type Formatter } from "./formatters/index.js";
+
+export abstract class BaseCommand extends Command {
+  static baseFlags = {
+    format: Flags.custom<Formatter>({
+      parse: async (input: string) => getFormat(input as Formats),
+      default: async () => getFormat("text"),
+      helpValue: `<${availableFormats.join("|")}>`,
+      description: "Output format",
+    })(),
+  };
+}
diff --git a/packages/cli/src/commands/extremes.ts b/packages/cli/src/commands/extremes.ts
new file mode 100644
index 0000000..0ded6be
--- /dev/null
+++ b/packages/cli/src/commands/extremes.ts
@@ -0,0 +1,85 @@
+import { BaseCommand } from "../command.js";
+import { Flags } from "@oclif/core";
+import { findStation, nearestStation } from "neaps";
+
+export default class Extremes extends BaseCommand {
+  static override description = "Get tide extremes for a station";
+
+  static override flags = {
+    station: Flags.string({
+      description: "Use the specified station ID",
+      helpValue: "<station-id>",
+      exclusive: ["near", "ip"],
+    }),
+    ip: Flags.boolean({
+      default: false,
+      description: "Use IP geolocation to find nearest station",
+      exclusive: ["station", "near"],
+    }),
+    near: Flags.string({
+      description: "Use specified lat,lon to find nearest station",
+      helpValue: "lat,lon",
+      exclusive: ["station", "ip"],
+    }),
+    start: Flags.string({
+      description: "ISO date",
+      default: new Date().toISOString(),
+      parse: async (input: string) => new Date(input).toISOString(),
+      noCacheDefault: true,
+      validate: (input: string) => new Date(input),
+      helpValue: "YYYY-MM-DD",
+    }),
+    end: Flags.string({
+      description: "ISO date",
+      helpValue: "YYYY-MM-DD",
+    }),
+    units: Flags.string({
+      description: "Units for output (meters or feet)",
+      default: "meters",
+      helpValue: "<meters|feet>",
+    }),
+  };
+
+  public async run(): Promise<void> {
+    const { flags } = await this.parse(Extremes);
+
+    const station = await getStation(flags);
+    const start = new Date(flags.start);
+    const end = flags.end ? new Date(flags.end) : new Date(start.getTime() + 72 * 60 * 60 * 1000);
+
+    const prediction = station.getExtremesPrediction({
+      start,
+      end,
+      units: flags.units as "meters" | "feet",
+    });
+
+    flags.format.extremes(prediction);
+  }
+}
+
+async function getStation({
+  station,
+  near,
+  ip,
+}: {
+  station?: string;
+  near?: string;
+  ip?: boolean;
+}) {
+  if (station) {
+    return findStation(station);
+  }
+
+  if (near) {
+    const [lat, lon] = near.split(",").map(Number);
+    return nearestStation({ latitude: lat, longitude: lon });
+  }
+
+  if (ip) {
+    const res = await fetch("https://reallyfreegeoip.org/json/");
+    if (!res.ok) throw new Error(`Failed to fetch IP geolocation: ${res.statusText}`);
+    return nearestStation(await res.json());
+  } else {
+    throw new Error("No station specified. Use --station or --ip flag.");
+  }
+}
diff --git a/packages/cli/src/commands/stations.ts b/packages/cli/src/commands/stations.ts
new file mode 100644
index 0000000..408eca5
--- /dev/null
+++ b/packages/cli/src/commands/stations.ts
@@ -0,0 +1,54 @@
+import { BaseCommand } from "../command.js";
+import { Args, Flags } from "@oclif/core";
+import { stations } from "@neaps/tide-database";
+import { stationsNear } from "neaps";
+
+export default class Stations extends BaseCommand {
+  static override description = "List available tide stations";
+
+  static override args = {
+    query: Args.string({ description: "Station name or id" }),
+  };
+
+  static override flags = {
+    all: Flags.boolean({
+      description: "List all stations. Same as setting --limit=0",
+      exclusive: ["limit"],
+    }),
+    limit: Flags.integer({
+      description: "Limit number of stations displayed",
+      default: 10,
+      exclusive: ["all"],
+    }),
+    near: Flags.string({
+      description: "Use specified lat,lon to find nearest stations",
+      helpValue: "<lat,lon>",
+    }),
+  };
+
+  public async run(): Promise<void> {
+    const { args, flags } = await this.parse(Stations);
+
+    if (flags.all) flags.limit = 0;
+
+    let list = stations;
+
+    if (flags.near) {
+      const [lat, lon] = flags.near.split(",").map(Number);
+      list = stationsNear({ lat, lon }, Number(flags.limit));
+    }
+
+    if (args.query) {
+      const search = args.query.toLowerCase();
+      list = list.filter((s) => s.id.includes(search) || s.name.toLowerCase().includes(search));
+    }
+
+    if (flags.limit > 0) {
+      list = list.slice(0, flags.limit);
+    }
+
+    if (!list.length) throw new Error("No stations found");
+
+    flags.format.listStations(list);
+  }
+}
diff --git a/packages/cli/src/formatters/index.ts b/packages/cli/src/formatters/index.ts
new file mode 100644
index 0000000..c020c90
--- /dev/null
+++ b/packages/cli/src/formatters/index.ts
@@ -0,0 +1,32 @@
+import text from "./text.js";
+import json from "./json.js";
+import type { Station } from "@neaps/tide-database";
+import { getExtremesPrediction } from "neaps";
+
+export const formatters = {
+  text,
+  json,
+};
+
+export type Formats = keyof typeof formatters;
+export type FormatterFactory = (stdout: NodeJS.WriteStream) => Formatter;
+// TODO: export a proper type from neaps
+export type ExtremesPrediction = ReturnType<typeof getExtremesPrediction>;
+
+export interface Formatter {
+  extremes(prediction: ExtremesPrediction): void;
+  listStations(stations: Station[]): void;
+}
+
+export const availableFormats = Object.keys(formatters) as Formats[];
+
+export default function getFormat(
+  format: Formats,
+  stdout: NodeJS.WriteStream = process.stdout,
+): Formatter {
+  const formatter = formatters[format];
+  if (!formatter) {
+    throw new Error(`Unknown output format: ${format}`);
+  }
+  return formatter(stdout);
+}
diff --git a/packages/cli/src/formatters/json.ts b/packages/cli/src/formatters/json.ts
new file mode 100644
index 0000000..197c036
--- /dev/null
+++ b/packages/cli/src/formatters/json.ts
@@ -0,0 +1,16 @@
+import type { FormatterFactory } from "./index.js";
+
+const formatter: FormatterFactory = function (stdout) {
+  function write(data: object) {
+    stdout.write(JSON.stringify(data, null, 2));
+    stdout.write("\n");
+  }
+
+  return {
+    extremes: write,
+    listStations: write,
+    toString: () => "text",
+  };
+};
+
+export default formatter;
diff --git a/packages/cli/src/formatters/text.ts b/packages/cli/src/formatters/text.ts
new file mode 100644
index 0000000..7e358b0
--- /dev/null
+++ b/packages/cli/src/formatters/text.ts
@@ -0,0 +1,31 @@
+import type { FormatterFactory } from "./index.js";
+import { Console } from "console";
+
+const formatter: FormatterFactory = function (stdout) {
+  const console = new Console(stdout);
+
+  return {
+    extremes(prediction) {
+      console.log(`Station: ${prediction.station.name}`);
+      console.log(`Datum: ${prediction.datum}`);
+
+      prediction.extremes.forEach((extreme) => {
+        console.log(
+          `${extreme.time.toISOString()} | ${extreme.high ? "High" : "Low "} | ${extreme.level.toFixed(
+            2,
+          )} ${prediction.units === "meters" ? "m" : "ft"}`,
+        );
+      });
+    },
+
+    listStations(stations) {
+      stations.forEach((s) => {
+        console.log(`${s.id}\t${s.name} (${s.country})`);
+      });
+    },
+
+    toString: () => "text",
+  };
+};
+
+export default formatter;
diff --git a/packages/cli/test/commands/extremes.test.ts b/packages/cli/test/commands/extremes.test.ts
new file mode 100644
index 0000000..a19b326
--- /dev/null
+++ b/packages/cli/test/commands/extremes.test.ts
@@ -0,0 +1,110 @@
+import { describe, test, expect } from "vitest";
+import { runCommand } from "@oclif/test";
+import nock from "nock";
+
+nock.disableNetConnect();
+
+describe("extremes", async () => {
+  function run(args: string[]) {
+    return runCommand(["extremes", ...args]);
+  }
+
+  test("--help", async () => {
+    const { stdout } = await run(["--help"]);
+    expect(stdout).toMatch(/extremes/);
+    expect(stdout).toMatch(/--station/);
+    expect(stdout).toMatch(/--start/);
+    expect(stdout).toMatch(/--end/);
+    expect(stdout).toMatch(/--format/);
+  });
+
+  test("--station <id>", async () => {
+    const { stdout } = await run(["--station", "9414290", "--start", "2026-01-01"]);
+    expect(stdout).toMatch(/SAN FRANCISCO/);
+  });
+
+  test("--near 22.24,-75.75", async () => {
+    const { stdout } = await run(["--near", "22.24,-75.75"]);
+    expect(stdout).toMatch(/Nurse Channel/);
+  });
+
+  test("--ip", async () => {
+    nock("https://reallyfreegeoip.org").get("/json/").reply(200, {
+      latitude: 25.0565,
+      longitude: -77.3524,
+    });
+
+    const { stdout } = await run(["--ip"]);
+    expect(stdout).toMatch(/Nassau, New Providence Island/);
+  });
+
+  describe("--start", () => {
+    test("defaults to today", async () => {
+      const today = new Date().toISOString().split("T")[0];
+
+      const { stdout } = await run(["--station", "9414290"]);
+      expect(stdout).toMatch(new RegExp(today));
+    });
+
+    test("accepts partial date", async () => {
+      const { stdout } = await run(["--station", "9414290", "--start", "2025-12-25"]);
+      expect(stdout).toMatch(/2025-12-25/);
+    });
+
+    test("accepts full date", async () => {
+      const { stdout } = await run(["--station", "9414290", "--start", "2025-12-25T00:00:00Z"]);
+      expect(stdout).toMatch(/2025-12-25/);
+    });
+
+    test("with invalid input", async () => {
+      const { error } = await run(["--station", "9414290", "--start", "invalid-date"]);
+      expect(error?.message).toMatch(/Invalid time value/);
+    });
+  });
+
+  describe("--end", () => {
+    test("defaults to 72 hours from start", async () => {
+      const { stdout } = await run(["--station", "9414290", "--start", "2025-12-25"]);
+      expect(stdout).toMatch(/2025-12-27/);
+    });
+
+    test("accepts partial date", async () => {
+      const { stdout } = await run([
+        "--station",
+        "9414290",
+        "--start",
+        "2025-12-25",
+        "--end",
+        "2025-12-26",
+      ]);
+      expect(stdout).toMatch(/2025-12-25/);
+      expect(stdout).not.toMatch(/2025-12-26/);
+    });
+  });
+
+  describe("--format", () => {
+    test("json", async () => {
+      const { stdout } = await run(["--station", "9414290", "--format", "json"]);
+      const result = JSON.parse(stdout);
+      expect(result.station.name).toMatch(/SAN FRANCISCO/i);
+      expect(result.datum).toEqual("MLLW");
+      expect(result.extremes.length).toBeGreaterThan(0);
+    });
+  });
+
+  test("no station specified throws error", async () => {
+    const { error } = await run([]);
+    expect(error?.message).toMatch(/No station specified/);
+  });
+
+  test("invalid station ID throws error", async () => {
+    const { error } = await run(["--station", "invalid-station-id-xyz"]);
+    expect(error?.message).toMatch(/Station not found/);
+  });
+
+  test("--ip with failed geolocation", async () => {
+    nock("https://reallyfreegeoip.org").get("/json/").reply(500);
+    const { error } = await run(["--ip"]);
+    expect(error?.message).toMatch(/Failed to fetch IP geolocation/);
+  });
+});
diff --git a/packages/cli/test/commands/stations.test.ts b/packages/cli/test/commands/stations.test.ts
new file mode 100644
index 0000000..11581df
--- /dev/null
+++ b/packages/cli/test/commands/stations.test.ts
@@ -0,0 +1,42 @@
+import { describe, expect, test } from "vitest";
+import { runCommand } from "@oclif/test";
+
+function run(args: string[]) {
+  return runCommand(["stations", ...args]);
+}
+
+describe("stations", () => {
+  test("lists default limited set", async () => {
+    const { stdout } = await run(["--format", "json"]);
+    const list = JSON.parse(stdout);
+
+    expect(list).toHaveLength(10);
+  });
+
+  test("supports --all while filtering by query", async () => {
+    const { stdout } = await run(["--all", "Nonopapa", "--format", "json"]);
+    const list = JSON.parse(stdout);
+
+    expect(list.length).toBeGreaterThan(0);
+    list.forEach((station: { id: string; name: string }) => {
+      const search = "nonopapa";
+      expect(
+        station.id.toLowerCase().includes(search) || station.name.toLowerCase().includes(search),
+      ).toBe(true);
+    });
+  });
+
+  test("finds nearest stations", async () => {
+    const { stdout } = await run(["--near", "37.8,-122.5", "--limit", "1", "--format", "json"]);
+    const list = JSON.parse(stdout);
+
+    expect(list).toHaveLength(1);
+    expect(list[0].source.id).toBe("9414275");
+  });
+
+  test("throws when no stations match", async () => {
+    const { error } = await run(["--format", "json", "this-will-not-match"]);
+
+    expect(error?.message).toMatch(/No stations found/);
+  });
+});
diff --git a/packages/cli/test/setup.ts b/packages/cli/test/setup.ts
new file mode 100644
index 0000000..f778a63
--- /dev/null
+++ b/packages/cli/test/setup.ts
@@ -0,0 +1,2 @@
+// Force to use cli directory as root for oclif
+process.env.OCLIF_TEST_ROOT = new URL("..", import.meta.url).pathname;
diff --git a/packages/cli/tsconfig.json b/packages/cli/tsconfig.json
new file mode 100644
index 0000000..d1b2c09
--- /dev/null
+++ b/packages/cli/tsconfig.json
@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "declaration": true,
+    "module": "nodenext",
+    "outDir": "dist",
+    "rootDir": "src",
+    "strict": true,
+    "target": "es2022",
+    "moduleResolution": "nodenext",
+    "resolveJsonModule": true,
+    "sourceMap": true
+  },
+  "include": ["./src/**/*"]
+}
diff --git a/packages/cli/vitest.config.ts b/packages/cli/vitest.config.ts
new file mode 100644
index 0000000..d6fdece
--- /dev/null
+++ b/packages/cli/vitest.config.ts
@@ -0,0 +1,8 @@
+import { defineProject } from "vitest/config";
+
+export default defineProject({
+  test: {
+    disableConsoleIntercept: true,
+    setupFiles: ["./test/setup.ts"],
+  },
+});