400 Sunny Isles, Sunny Isles Beach: What Buyers Should Check

400 Sunny Isles is the boater's address in Sunny Isles Beach — twin 20-story glass towers at 400 Sunny Isles Boulevard, completed in 2015, on the Intracoastal Waterway at the south end of the island, where the marina is not an amenity but the point. The two towers sit on 640 feet of bay frontage with a full-service 230-slip marina, and the slips are real property in their own right: the county records 116 deeded boat slips as separate folios, assessed individually, trading on their own deeds at a median of $143,000 in slip-only sales since 2023. The 230 residences run two to four bedrooms, from 1,091 to 3,140 square feet, with floor-to-ceiling glass, private elevator entry, and views that layer the bay, the ocean beyond, and Oleta River State Park to the south. Two things a buyer must understand before anything else: the county records the two towers as two separate condominiums — 400 Sunny Isles Condo East (133 homes) and 400 Sunny Isles Condo West (97 homes) — and their sale records do not match, so any price quoted for '400 Sunny Isles' without naming the tower is at best half a fact; and the market is thin, about one home in 20 trading per year, with 12 months of inventory, so a buyer who may need to sell quickly should price against the recorded band and not against asking prices. Monthly dues run about $0.93 to $1.25 per square foot — roughly $1,441 a month on a 1,553-square-foot two-bedroom — and one listing states the building has full reserves with no assessments, a claim worth verifying against the adopted budget before relying on it.

The facts

• Address: 400 Sunny Isles Boulevard, Sunny Isles Beach, FL 33160
• Completed: 2015
• Stories: 20 — twin towers
• Residences: 230 — in two separately recorded condominiums: 400 Sunny Isles Condo East, 133 homes, and 400 Sunny Isles Condo West, 97 homes
• Developer: Key International, with 13th Floor Investments
• Architect: Chad Oppenheim (Zilbert also credits Kobi Karp alongside Oppenheim; Apartments.com and Homes.com credit Jordan Karp LLC)
• Unit mix: one- to four-bedroom residences. East: 8 one-bedrooms, 44 two-bedrooms, 77 three-bedrooms, 4 four-bedrooms. West: 8 one-bedrooms, 32 two-bedrooms, 53 three-bedrooms, 4 four-bedrooms.
• Unit sizes: 1,091 to 3,140 sq ft in both towers; the median home is 1,687 sq ft in East and 1,688 sq ft in West
• Waterfront: Intracoastal Waterway, with 640 feet of bay frontage and a full-service 230-slip marina; boat slips up to 100 feet. The beach is a short trip across Collins Avenue; the building's amenity list includes beach access and beach rights.
• Boat slips: 116 deeded slips recorded by the county as separate folios, assessed individually (2026 assessed values $66,697–$361,569, median $104,761). Twenty qualified slip-only sales since 2023 at a median of $143,000; the largest was $480,000 in May 2024.
• Parking: two garage spaces per at least one listing (#1707); valet service is available building-wide
• Association: 400 Sunny Isles Condominium Association, (305) 328-8514

Amenities and day-to-day living

400 Sunny Isles runs a full-service program built around the water: a full-service marina with wet and dry slips, a flow-through pool deck with an oceanfront-style pool, a spa and hot tub, a fitness center, tennis courts, a poolside bar, a billiard room, a business center, a cabana, a car wash area, a clubhouse, a picnic area, a playground, a sauna, and beach access with beach rights. Residences have private elevator entry, floor-to-ceiling glass, and large terraces. The market is thin but steady. Thirteen sales were recorded in the twelve months to October 26, 2026, at a median of $1,100,000, or $655 per square foot, on the county record. Twenty-three residences were listed for sale in November 2026 at an average asking price of $672.63 per square foot, and at the current sales pace that is about 12 months of inventory. The two towers disagree with each other: over four years East traded at a median of $717 per square foot against West at $668 — East 7.3% dearer — while the county assesses West 1.9% higher. West is the only tower with a supportable four-year direction: its median moved from $657 to $650 per square foot, a change of 1.1%, on six qualified sales in 2023 and six in 2026. East has recorded exactly one qualified sale in 2026, so no direction can be read from it. Record sales: East's high is $2,600,000 for a 3,140 sq ft home in March 2022; West's is $2,850,000 for a 3,120 sq ft home in January 2015. Rentals listed in November 2026 include #1002 West (1,553 sq ft, two bedrooms plus den) at $6,200 a month and #521 East (1,329 sq ft, three bedrooms) at $5,700 a month.

What to check before you buy

• Monthly cost — verify the dues, don't take the range. Homes.com gives a monthly HOA range of $1,345 to $3,862, covering common areas, cable TV, internet, security, trash, and water. Per-unit examples land in a tighter band: #1707 West (1,553 sq ft) at $1,441 a month, #1401 West (1,688 sq ft) at $1,592 a month, #121 (1,313 sq ft) at $1,626 a month, #906 (1,690 sq ft) at $1,995 a month, #1519 (1,865 sq ft) at $2,058 a month, and #1605 (1,705 sq ft) at $2,126 a month — about $0.93 to $1.25 per square foot per month. That is the figure to confirm against the adopted budget for the specific unit and tower you are buying, including whether any special assessment is running. One listing for #1707 states 'NO ASSESSMENTS — Building has FULL RESERVES and very solid financially.' That is listing copy, not an association document — ask for the reserve study and the adopted budget before relying on it.
• The boat slip — a separate purchase, a separate negotiation. At this address a slip is real property, not an amenity: the county records 116 deeded slips as their own folios, assesses them individually, and lets them change hands on their own deed. A slip here is priced like a small piece of Miami real estate — a 2026 median assessed value of $104,761, and 20 qualified slip-only sales since 2023 at a median of $143,000. Ask early whether the home you are looking at comes with a slip, and if it does, whether it is deeded to that home or simply rented from someone who owns it. If it is not included, a slip is a second purchase with its own closing costs.
• Which tower you are buying — East and West do not price alike. The county records them as two separate condominiums, and their sale records do not match: East traded at a median of $717 per square foot over four years against West at $668, while the county assesses West higher. Any figure quoted for '400 Sunny Isles' without saying which tower it came from is, at best, half a fact. Price against the recorded sales for your tower, with the other tower's record as a cross-check — and note that East has recorded only one qualified sale in 2026, so its pricing conversation will lean on 2025 and on West.
• Milestone inspection — not due yet, but ask anyway. Florida milestone inspection rules generally apply at 30 years, or 25 years within 3 miles of the coast. This is a bay-side building completed in 2015, so its first milestone inspection falls around 2040 on the 25-year coastal rule — a derived estimate, not a confirmed date. At about eleven years old, this building is roughly fifteen years out from that first milestone, which is a better position than the older towers in the sweep — but confirm the association's own timeline, since inspection deadlines depend on the certificate of occupancy and local requirements.
• Subsidence — not on the study's list, which is a real positive. 400 Sunny Isles does not appear on the published list of 35 barrier-island buildings the University of Miami's 2024 InSAR study found settling between 2 and 8 centimeters from 2016 to 2023. The study's authors said no building was found unsafe, and the absence of 400 Sunny Isles from the list is a point in its favour, not a guarantee: ask the association whether any engineering review or monitoring has been done, and whether the milestone report addresses settlement at all, since heavy construction has continued all around the south end of the island.
• Reserves and assessments — one listing's claim, unverified. No building-wide reserve figure or assessment history was found in public sources beyond the single listing's 'full reserves, no assessments' statement. Ask for the reserve study and the last three years of board minutes before signing.
• Owner-occupancy — unverified. No owner-occupancy ratio was found in public sources. If you are financing, your lender will check it — confirm it before you are under contract, not after.
• Rentals — long-term only, six-month minimum. One building directory states long-term rentals only, and that seasonal rentals are possible with a minimum rental period of six months. Confirm the current lease rules, any rental caps, and the association approval process with the association before buying for income — and do not buy here expecting short-term rental income.
• Pets — dogs and cats allowed, with restrictions. CondoBlackBook's building record says 'Pets OK for owners & renters, Large Pets allowed for owners'; rental listings describe small dogs and large dogs as allowed, and Homes.com lists pets as allowed with restrictions. Confirm the current rules — including any size, number, or breed limits — with the association before you buy if a pet is part of the plan.

Who this building suits

400 Sunny Isles suits a buyer who actually wants the water access and is prepared to pay for it twice — once for the home and once for the slip. For that buyer, very little else in Sunny Isles Beach does the same job: 640 feet of bay frontage, a full-service 230-slip marina, and a deeded slip that is itself a six-figure asset. It also suits a buyer who wants a large, newer bay-side home — up to 3,140 square feet, 2015 construction, floor-to-ceiling glass and private elevator entry — at roughly $650 to $720 per square foot, with dues of about $0.93 to $1.25 per square foot. It is a poor fit for a buyer who needs to be confident of getting out quickly — about one home in 20 trades in a typical year, with 12 months of inventory — or who wants direct oceanfront, a small or low-priced entry, or short-term rental income. If you are choosing between this and another tower, send Mike the buildings you are comparing and he will walk through the finances with you, building by building.

Next step

Get the free Sunny Isles Beach Buyer's Building Guide — the ten questions to ask before you sign, applied to the tower you are actually considering. Or book a call with Mike to walk through 400 Sunny Isles together.