• Ulva Adans. accepted as Carex L.
• Ulva Haller (uncertain > unassessed)
• Ulva Linnaeus, 1753
• Ulva acanthophora (Kützing) H.S.Hayden, Blomster, Maggs, P.C.Silva, Stanhope & Waaland, 2003
• Ulva adhaerens Kaoru Matsumoto & S.Shimada, 2015
• Ulva adspersa Mertens ex Roth, 1806 accepted as Cutleria adspersa (Mertens ex Roth) De Notaris, 1842
• Ulva aetherea Poiret (uncertain)
• Ulva agarum (Gmelin) Poiret (uncertain)
• Ulva agarum (Gmelin) Woodward (uncertain)
• Ulva amamiensis Tanaka, 1956 accepted as Umbraulva amamiensis (Tanaka) Bae & I.K.Lee, 2001
• Ulva ambigua De Candolle, 1815
• Ulva ampullacea Poiret, 1808 (uncertain)
• Ulva anandii Amjad & Shameel, 1993
• Ulva angusta Setchell & N.L.Gardner, 1920 accepted as Ulva californica Wille, 1899
• Ulva aponina Meneghini (uncertain)
• Ulva appendiculata Schousboe (uncertain)
• Ulva aragoensis (Bliding) Maggs in Krupnik et al., 2018
• Ulva arasakii Chihara, 1969
• Ulva arbuscula Lagourgue & Payri, 2022
• Ulva ardreana M.Cormaci, G.Furnari & G.Alongi, 2013
• Ulva armoricana P.Dion, B.de Reviers & G.Coat, 1998 accepted as Ulva rigida C.Agardh, 1823
• Ulva articulata Hudson, 1762 accepted as Lomentaria articulata (Hudson) Lyngbye, 1819
• Ulva atomaria Woodward, 1797 accepted as Taonia atomaria (Woodward) J.Agardh, 1848
• Ulva atropurpurea Olivi, 1791 accepted as Porphyra atropurpurea (Olivi) De Toni, 1897
• Ulva atroviridis Levring, 1938
• Ulva attenuata (C.Agardh) Naccari, 1828 (uncertain)
• Ulva aurantiaca Poiret, 1808
• Ulva aureola C.Agardh, 1829 accepted as Capsosiphon fulvescens (C.Agardh) Setchell & N.L.Gardner, 1920
• Ulva australis Areschoug, 1854
• Ulva baltica Areschoug accepted as Monostroma balticum Wittrock, 1866
• Ulva bartayresiana (Lamouroux) Martius, 1833 accepted as Dictyota bartayresiana J.V.Lamouroux, 1809
• Ulva batuffolosa Lagourgue & Payri, 2022
• Ulva belangeri (Montagne) De Toni, 1889 (uncertain)
• Ulva bertolonii C.Agardh, 1823 accepted as Ulva linza Linnaeus, 1753
• Ulva beytensis Thivy & Sharma, 1966
• Ulva biflagellata Bliding, 1944
• Ulva bifrons Ardré, 1967 accepted as Ulva ardreana M.Cormaci, G.Furnari & G.Alongi, 2013
• Ulva billardierei Mertens ex C.Agardh (uncertain)
• Ulva binalis Hassall
• Ulva blidingii Alongi, Cormaci & G.Furnari, 2014
• Ulva blyttii Areschoug, 1850 accepted as Ulvaria obscura var. blyttii (Areschoug) Bliding, 1969
• Ulva brevistipita V.J.Chapman, 1956
• Ulva brisbanensis L.G.Kraft, Kraft & R.F.Waller, 2010
• Ulva bulbosa (Suhr) Hariot, 1889 accepted as Ulva hookeriana (Kützing) H.S.Hayden, Blomster, Maggs, P.C.Silva, Stanhope & Waaland, 2003
• Ulva bulbosa A.P.de Candolle, 1805 accepted as Saccorhiza polyschides (Lightfoot) Batters, 1902
• Ulva bulbosa Pasilot de Beauvois, 1805
• Ulva bulbosa var. australasica (J.Agardh) Hariot
• Ulva bulbosa var. intestinalis (Linnaeus) Hariot, 1889 accepted as Ulva intestinalis Linnaeus, 1753
• Ulva bulbosa var. peruana Hariot, 1889 accepted as Enteromorpha bulbosa (Suhr) Montagne, 1846 accepted as Ulva hookeriana (Kützing) H.S.Hayden, Blomster, Maggs, P.C.Silva, Stanhope & Waaland, 2003
• Ulva bullata A.P.de Cancolle, 1807 accepted as Nostoc bullatum (A.P.de Candolle) Duby, 1830
• Ulva bullata Poiret, 1808 accepted as Rivularia bullata Berkeley ex Bornet & Flahault, 1886
• Ulva bullosa Roth, 1806 accepted as Monostroma bullosum (Roth) Thuret, 1854
• Ulva burmanica (Zeller) De Toni, 1889
• Ulva bursa (Linnaeus) Poiret (uncertain)
• Ulva byssoides Mertens
• Ulva caespitosa Withering, 1776 accepted as Catenella caespitosa (Withering) L.M.Irvine, 1976
• Ulva calendulifolia (S.G.Gmelin) J.F.Gmelin
• Ulva californica Wille, 1899
• Ulva calophylla (Carm.) Sprengel (uncertain)
• Ulva capensis J.E. Areschoug, 1851 accepted as Ulva uncialis (Kützing) Montagne, 1850
• Ulva capillaris Hudson, 1778 accepted as Chondria capillaris (Hudson) M.J.Wynne, 1991
• Ulva caprina Gunnerus, 1772 accepted as Palmaria palmata (Linnaeus) F.Weber & D.Mohr, 1805
• Ulva caudata Schousboe (uncertain)
• Ulva caulescens J.V.Lamouroux
• Ulva cavernosa Forsskål, 1775 accepted as Dictyosphaeria cavernosa (Forsskål) Børgesen, 1932
• Ulva ceranoides W.Withering
• Ulva chaetomorphoides (Børgesen) H.S.Hayden, Blomster, Maggs, P.C.Silva, Stanhope & Waaland, 2003
• Ulva chaugulii M.G.Kavale & M.A.Kazi, 2016
• Ulva ciliata (Hudson) De Candolle, 1805 accepted as Calliblepharis ciliata (Hudson) Kützing, 1843
• Ulva cinerea Martens ex De Notaris
• Ulva cirrosa Schousboe (uncertain)
• Ulva clathrata (Roth) C.Agardh, 1811
• Ulva clathrata f. abbreviata Le Jolis, 1863
• Ulva clathrata f. ambigua Le Jolis, 1863
• Ulva clathrata f. foeniculacea Le Jolis, 1863
• Ulva clathrata f. gracilis Le Jolis, 1863 accepted as Ulva clathrata (Roth) C.Agardh, 1811
• Ulva clathrata f. nudiuscula Le Jolis, 1863 (uncertain)
• Ulva clathrata f. prostrata Le Jolis, 1863 accepted as Ulva clathrata (Roth) C.Agardh, 1811
• Ulva clathrata f. robusta Le Jolis
• Ulva clathrata f. tenuis Le Jolis
• Ulva clathrata f. tenuissima Van Heurck
• Ulva clathrata var. agardhiana Le Jolis
• Ulva clathrata var. confervoides C.Agardh, 1817
• Ulva clathrata var. erecta (Lyngbye) Le Jolis
• Ulva clathrata var. rothiana Le Jolis
• Ulva clathrata var. uncinata (Lyngbye) C.Agardh
• Ulva clathratioides L.G.Kraft, Kraft & R.F.Waller, 2010 accepted as Ulva torta (Mertens) Trevisan, 1842
• Ulva clathrus (Gmelin) Poiret
• Ulva clathrus (S.G.Gmelin) Woodward, 1797 accepted as Thalassiophyllum clathrus (S.G.Gmelin) Postels & Ruprecht, 1840
• Ulva coccinea Hudson, 1778
• Ulva coccinea Poiret, 1808 accepted as Dudresnaya verticillata (Withering) Le Jolis, 1863
• Ulva compressa Forsskål, 1775 accepted as Ulva compressa Linnaeus, 1753
• Ulva compressa Linnaeus, 1753
• Ulva compressa var. abbreviata W.S.Atmadja & Prud'homme van Reine, 2014
• Ulva compressa var. byssoides Mertens, 1824
• Ulva compressa var. byssoides Naccari, 1824
• Ulva compressa var. crinita (Nees) C.Agardh
• Ulva compressa var. crinita (Roth) C.Agardh, 1823
• Ulva compressa var. crinita G.Martens, 1824
• Ulva compressa var. crispa Zanardini