How You Actually Get On and Off Belvedere's Islands

Why Belvedere Is an Island at All

Belvedere Island and Corinthian Island are genuine natural landforms -- composed of Franciscan Complex sandstone and greenstone bedrock, the same geological formation underlying much of the Marin Peninsula's hills -- separated from the Tiburon Peninsula mainland by what was originally open marsh and tidal water. San Francisco investors organized as the Belvedere Land Company bought the island in 1890 and began developing it as a summer retreat; through the early 20th century, the marsh separating it from Tiburon Point was progressively filled and paved for direct road access, with the first state highway crossing built in 1930. Today, two low causeways -- Beach Road and San Rafael Avenue -- carry that road connection, and the fill used to build them is what impounds the tidal Belvedere Lagoon between Belvedere Island and Corinthian Island.

That history matters for an honest understanding of what 'island' means here: the islands themselves are natural, but the connection to the mainland is entirely artificial fill, built specifically to make car access possible. Belvedere has not been water-isolated in the way a ferry-only island is for close to a century -- but it remains, geologically and administratively, a genuine island city, distinct from Tiburon's larger peninsula.

No Ferry, No Golf Cart -- Just an Ordinary Car

Unlike the ferry-dependent or golf-cart-only islands profiled elsewhere on this site, reaching Belvedere requires nothing more than driving an ordinary passenger car across Beach Road or San Rafael Avenue from Tiburon Boulevard -- no toll, no reservation, no seasonal schedule, no vehicle restriction. A moving truck, a contractor's equipment trailer, a delivery van: all of them simply drive in, the same as they would to any mainland address. There is no barge, no freight-crossing fee, and no luggage-weight limit of the kind that governs a ferry-only island's logistics.

This is a genuine, meaningful practical difference from Belvedere's ISLAND-type sibling markets on this site, and a buyer coming from research on a ferry-dependent island should recalibrate expectations accordingly: day-to-day access here is essentially identical to any other Marin County address, not a scheduled, weather-dependent boat crossing.

Two Routes In, Not One -- a Real Redundancy Most Ferry Islands Don't Have

Because Belvedere is connected by two separate causeways rather than one, there's a real structural redundancy that a single-bridge or single-ferry-route island doesn't have: if one causeway were closed for repair or flooding, the other would, in principle, still carry traffic. This page did not find or confirm how the city or Marin County would actually manage traffic during a simultaneous closure of both routes, or whether the two causeways connect to different points on Tiburon Boulevard versus converging quickly onto the same road -- a buyer with a real interest in worst-case access planning should ask the City of Belvedere directly rather than assume full redundancy based on there being two named routes.

The Real Logistics Risk: the Causeways Themselves Need Work

The genuine 'island logistics' story in Belvedere isn't a ferry timetable -- it's that the two causeways carrying all vehicle access are also, structurally, fill-built levees holding back San Francisco Bay from the Belvedere Lagoon, and the city's own reporting describes erosion actively undermining the Beach Road seawall's footing, with a roughly $3 million repair phase budgeted for fiscal year 2025-26. The city's larger, roughly $28 million Critical Infrastructure Project specifically targets seismic strengthening for these same causeways, precisely because a serious earthquake damaging them would create an access failure and a flood failure simultaneously, not two separate problems.

This is a real, practical access-reliability consideration distinct from anything a ferry-island buyer would research: rather than asking 'what's the ferry schedule and how often does weather cancel it,' a Belvedere buyer's honest access-reliability question is 'what's the current structural condition of these two causeways, and what does the city's active repair timeline look like.' Ask the City of Belvedere directly for the current status of both the Beach Road Sea Wall Stabilization Project and the broader Critical Infrastructure Project.

A Real Historical Water-Access Story: the Drawbridge That Once Let Arks Pass

Before the fixed causeways reached their current form, the passage between Belvedere Cove and the sheltered Belvedere Lagoon was crossed by an actual drawbridge, not a fixed span -- and that drawbridge played a real, documented role in the community's early-20th-century life. Each winter, the drawbridge would open to let the era's floating "ark" houseboats and the Corinthian Yacht Club's pleasure boats pass from the open cove into the calmer lagoon for safe winter mooring, with a well-attended spring procession moving them back out to the cove each year. When the drawbridge was later converted to a fixed span, the arks could no longer winter in the lagoon at all, and many were towed away and hauled ashore elsewhere -- some becoming the shops that today line Ark Row on Tiburon's Main Street.

That's a genuine, sourced piece of local infrastructure history worth knowing: Belvedere's causeway system wasn't always simply a fixed road -- for a period, it included a working drawbridge that governed real seasonal water traffic, a detail that connects the islands' current road-access reality to their earlier, genuinely more water-dependent past.

No On-Island Commerce Means Every Errand Crosses a Causeway

Even though Belvedere's access itself is ordinary and unrestricted, day-to-day life here still involves routinely crossing a causeway for nearly everything: Belvedere has essentially no grocery store, gas station, or retail district of its own (see the Practical Living page), so groceries, fuel, and most errands mean a short drive or walk across Beach Road or San Rafael Avenue into Tiburon. This is a genuinely different kind of 'island logistics' than a ferry schedule -- it's not about whether you can leave, but about how often you'll be making that short causeway crossing as a routine, daily fact of life.

What This Means for a First-Time Buyer

Don't research Belvedere expecting ferry schedules, golf-cart rules, or barge freight logistics -- none of that applies here. Do expect an ordinary car-accessible city with a genuinely distinctive structural quirk: its two access causeways are also its flood-control and now-actively-being-repaired seismic infrastructure, funded through a real, current, multi-million-dollar city capital program. Ask the City of Belvedere directly about the current status of that infrastructure work, and treat the islands' natural-bedrock-versus-fill-causeway distinction, covered in more depth on the Flood Zones and Hurricane & Storm Risk pages, as the real substance behind Belvedere's ISLAND classification -- not a ferry or golf-cart lifestyle that simply doesn't exist here.